1. What is data?
Data is a collection of raw, facts and figures that is use in different place we can store anything in database is called data.
2. What is database?
Collection of organized data which can easily managed access, understand, and update.
3. What is database management system?
Any programming environment used to create containers, to manage human data, can be conceptualized as a Data Management System
4. What is table?
It is a set of elements that is consist of rows and columns in which we can store our data. In any table we define specified no, of columns and there are many no. of rows are available in table that is use for store the data row wise.
5. What is column?
Column is a one element of table that is use logically vertical shape in table. We define specified no. of columns in one table then store data in it.
6. What is row?
Rows are also second element of table that is use for store the data in table as a horizontally shape. We can enter many rows in one table. In database terms we can say one record to one row in table.
7. What is primary key?
A primary is uniquely identifies a row of the table this key ensure two things one is that null value does not allow and duplicate value also not allowed in table. A table must always have one and only one primary key. Primary key value is normally employee code, Driving license code, NIC code etc.
8. What is foreign key?
A foreign key is a references or a link between one table and another. The foreign key can be used to cross reference tables. A foreign has a link with parent table (that have primary key value). Suppose we have one table with primary key and w have second table that have foreign key and have a relation with parent table than we must enter the values in second table that is totally related with parent table.
9. What is unique key?
Unique key does not accept duplicate values but accept null values in oracle. Unique key is very much related with primary key in primary key we cannot enter NULL value and also duplicate value. But on the other hand in unique key we can enter NULL value but not duplicate value. For example in employee database we set Driving license no. unique because one employee have unique license no. and some employees have not.
10. What is the difference between primary key and unique key?
Unique key does not accept duplicate values but accept null values and primary key does not accept both two either NULL or duplicate data.
11. What is Null constraint?
The columns that have NULL constraint must fill with some data. A column in a table can be specified not null. It’s not possible to insert a null in such a column we cannot leave any column empty in tables that have NULL constraint. It should be fill with no matter with duplication of that.
12. What is the maximum no. of column in oracle table?
The maximum no. of columns is 255.
13. Is COMMIT statement can be use in database trigger?
We cannot use any transaction control statement (like commit, rollback, savepoint etc.) into the body of a trigger. But oracle provides a facility called Autonomous Transactions through which you can achieve this. You add that piece of the code, which contains commit, in some block and make that block as Autonomous Transaction and call or use that block into your trigger.
What are the different types of reports?
· Tabular
· Master Detail Reports
· Form Reports
· Form Letter Reports
· Mailing Labels Reports
· Matrix Reports
What are Anchors in reports builder?
An anchor defines the actual position of an object. Anchors are used to determine the vertical and horizontal positioning of a child object relative to its parent.
An anchor defines the actual position of an object. Anchors are used to determine the vertical and horizontal positioning of a child object relative to its parent.
What are the different types of anchors in Reports?
A There are two types of anchors in Oracle Reports:
· Implicit (Creates when a report will run)
· Explicit (Anchors you create)
What are different types of report triggers also define their order of firing ?
There are five reports trigger with order:
1-Before Parameter Form
2-After Parameter Form
3-Before Report
4-Between Pages
5-After Report
There are five reports trigger with order:
1-Before Parameter Form
2-After Parameter Form
3-Before Report
4-Between Pages
5-After Report
Before Form Trigger:
It will Fires before the Run time Parameter Form that will displayed on screen. By using this trigger you can change the value of the parameters.
It will Fires before the Run time Parameter Form that will displayed on screen. By using this trigger you can change the value of the parameters.
After Form Trigger:
Fires after the Run time Parameter Form is displayed. From this trigger, you can access parameters and check their values. This trigger can also be used to change parameter values or, if an error occurs, return to the Runtime Parameter Form.
Fires after the Run time Parameter Form is displayed. From this trigger, you can access parameters and check their values. This trigger can also be used to change parameter values or, if an error occurs, return to the Runtime Parameter Form.
Before Report Trigger:
It will Fires before the report is executed but after queries are parsed and data is fetched.
It will Fires before the report is executed but after queries are parsed and data is fetched.
Between Pages Trigger:
Fires before each page of the report is formatted, except the very first page. This trigger can be used for customized page formatting. (Note : In the Previewer, this trigger only fires the first time that you go to a page. If you subsequently return to the page, the trigger does not fire again.)
Fires before each page of the report is formatted, except the very first page. This trigger can be used for customized page formatting. (Note : In the Previewer, this trigger only fires the first time that you go to a page. If you subsequently return to the page, the trigger does not fire again.)
After Report Trigger:
Fires after you exit the Previewer, or after report output is sent to a specified destination, such as a file, a printer, or an Oracle*Mail userid. This trigger can be used to clean up any initial processing that was done, such as deleting tables. Note, however, that this trigger always fires, whether or not your report completed successfully.
Fires after you exit the Previewer, or after report output is sent to a specified destination, such as a file, a printer, or an Oracle*Mail userid. This trigger can be used to clean up any initial processing that was done, such as deleting tables. Note, however, that this trigger always fires, whether or not your report completed successfully.
Format Triggers :
Format Triggers are PL/SQL functions executed before the object is formatted. The trigger can be used to dynamically change the formatting attributes of the object.
What are Placeholder Columns ?
A placeholder is a logical column for which you can conditionally set the datatype and value via PL/SQL or a user exit. Placeholder columns are useful when you want to selectively populate a column with a value.
A placeholder is a logical column for which you can conditionally set the datatype and value via PL/SQL or a user exit. Placeholder columns are useful when you want to selectively populate a column with a value.
What are the different page layout sections in Oracle Reports ?
A report has three main sections:
1-Report header pages
2-Report body/margin pages
3-Report trailer pages
A report has three main sections:
1-Report header pages
2-Report body/margin pages
3-Report trailer pages
What are different types of parameters?
There are two types of parameters:
1-System Parameters
2-User defined (bind and lexical) parameters
There are two types of parameters:
1-System Parameters
2-User defined (bind and lexical) parameters
What is the difference between Bind and Lexical parameter?
1-Bind parameters are used to replace a single value in SQL or PL/SQL, such as a character string, number, or date.
2-Lexical parameters are placeholders for text that you embed in a SELECT statement. Use Lexical reference when you want the parameter to substitute multiple values at runtime. You can use lexical references to replace the clauses appearing after SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING, CONNECT BY, and START WITH.
1-Bind parameters are used to replace a single value in SQL or PL/SQL, such as a character string, number, or date.
2-Lexical parameters are placeholders for text that you embed in a SELECT statement. Use Lexical reference when you want the parameter to substitute multiple values at runtime. You can use lexical references to replace the clauses appearing after SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING, CONNECT BY, and START WITH.
Define different types of Matrix report ?
1-Single query
2-Multi query
3-Nested Query
4-Matrix Break
1-Single query
2-Multi query
3-Nested Query
4-Matrix Break
How can you print one record per page in the output?
You can set the maximum records per page property of the Repeating frame to
You can set the maximum records per page property of the Repeating frame to
What is ‘page protect’ property in report builder?
Page protect property for an object indicates whether to try to keep the entire object and its contents on the same logical page. Checking Page Protect means that if the contents of the object cannot fit on the current logical page, the object and all of its contents will be moved to the next logical page.
Page protect property for an object indicates whether to try to keep the entire object and its contents on the same logical page. Checking Page Protect means that if the contents of the object cannot fit on the current logical page, the object and all of its contents will be moved to the next logical page.
What is the ‘Print Condition Type’ property?
‘Print Condition Type’ property specifies the frequency with which you want the object to appear in the report. The Print Condition Type options indicate the logical page(s) on which the object should be triggered to print with regard to the Print Condition Object.
‘Print Condition Type’ property specifies the frequency with which you want the object to appear in the report. The Print Condition Type options indicate the logical page(s) on which the object should be triggered to print with regard to the Print Condition Object.
What are the various values of the ‘Print Condition Type’ property in Reports ?
The various values are :1-All:
All means the object and all of its contents will be printed on all logical pages of the Print Condition Object. The object will be repeated on any overflow pages of the Print Condition Object and will be truncated at the logical page boundary, if necessary.2-All but First:
All but First means the object and all of its contents will be printed on all logical pages of the Print Condition Object except the first logical page. The object will be formatted only on overflow pages of the Print Condition Object and will be truncated at the logical page boundary, if necessary.3-All but Last:
All but Last means the object and all of its contents will be printed on all logical pages of the Print Condition Object except the last logical page. The object will be repeated on any overflow pages of the Print Condition Object except the last one and will be truncated at the logical page boundary, if necessary.4-Default:
Default means that Oracle Reports will use object positioning to set the Print Condition Type to either *First or *Last for you.5-First:
First means that the object and all of its contents will only be printed on the first logical page of the Print Condition Object. The object will be formatted and will overflow to subsequent pages, if necessary.6-Last:
Last means that the object and all of its contents will only be printed on the last logical page of the Print Condition Object. The object will be formatted after the Print Condition Object and will overflow to subsequent pages, if necessary.
The various values are :1-All:
All means the object and all of its contents will be printed on all logical pages of the Print Condition Object. The object will be repeated on any overflow pages of the Print Condition Object and will be truncated at the logical page boundary, if necessary.2-All but First:
All but First means the object and all of its contents will be printed on all logical pages of the Print Condition Object except the first logical page. The object will be formatted only on overflow pages of the Print Condition Object and will be truncated at the logical page boundary, if necessary.3-All but Last:
All but Last means the object and all of its contents will be printed on all logical pages of the Print Condition Object except the last logical page. The object will be repeated on any overflow pages of the Print Condition Object except the last one and will be truncated at the logical page boundary, if necessary.4-Default:
Default means that Oracle Reports will use object positioning to set the Print Condition Type to either *First or *Last for you.5-First:
First means that the object and all of its contents will only be printed on the first logical page of the Print Condition Object. The object will be formatted and will overflow to subsequent pages, if necessary.6-Last:
Last means that the object and all of its contents will only be printed on the last logical page of the Print Condition Object. The object will be formatted after the Print Condition Object and will overflow to subsequent pages, if necessary.
What is the difference when Flex mode is mode “ON” & when it is “OFF”?
When we set flex mode is ON then reports automatically resizes the parent when the child is resized.
When we set flex mode is ON then reports automatically resizes the parent when the child is resized.
What is the difference when confine mode is “ON” and when it is “OFF”?
When we set confine mode is “ON” thenobject cannot be moved outside its parent in the report layout.
When we set confine mode is “ON” thenobject cannot be moved outside its parent in the report layout.
What is the minimum number of groups that is required in matrix report?
Four groups are required for a matrix reports.
Four groups are required for a matrix reports.
What is the lock option in reports layout in oracle reports builder?
when we set lock option we cannot move the fields in the layout editor outside the frame. This is very useful for maintaining the fields.
when we set lock option we cannot move the fields in the layout editor outside the frame. This is very useful for maintaining the fields.
What are different types of column in reports?
There are 3 types of columns in the reports builder:
1-Placeholder Column
2-Formula Column
3-Summary Column
What is SQL statement?There are 3 types of columns in the reports builder:
1-Placeholder Column
2-Formula Column
3-Summary Column
SQL stands for Structured Query Language that is use for updating, deleting and inserting the information from databases. SQL is an ANSI and ISO standard and is the de-facto standard database query language. Oracle database also support this language.
What are database triggers and how many types of triggers?
Database triggers are a set of code that run or fire automatically when the specific operation will performed like Insert, Update and Delete. They are store procedures that are auto configure and fire when certain events take place in database.
There are two types of triggers
1- Tables level trigger
2- Row level trigger
Table level trigger are fire at one time but row level trigger fire on every row or on any transaction in the table.
What are the means of values of: new and: old in the trigger?
These two: new and: old are use in database triggers. These are basically use for referencing the trigger value by using triggers. For example we want to update anything in table and this table have database trigger on After Update then we use these two keywords for updating the values again this table.
What is the Mutating in the trigger?
The mutating will occur when in Oracle when the table that originally fired the triggering event is being accessed in the body of the trigger code, directly or implicitly in a procedure, or in a nested trigger called from the trigger body. This is because the table is in middle of a transaction, and referencing the same table again in the middle of the updating action causes the trigger to mutate.
Can we write a trigger for view?
Yes we can write a trigger on view by using key word “instead of” but did not use Before or After option on trigger.
Can we create a view on another view?
Yes we can create a view on another view.
What are the advantages of view?
1- Restrict the data and column s of the base tables.
2- Use complex quires easy and show the data of complex quires.
3- Make different views according to requirement on many on table.
4- We can hide business rules by using view.
What are function and how many types of functions?
Functions or user defined function are set of SQL/PLSQL code that are store in database and return the value. In function some data is manipulating by using some statement then return a specific value.
What is the difference between row level and Table level triggers?
Table level trigger are fire at one time but row level trigger fire on every row or on any transaction in the table.
What is the difference between Database triggers and Form level triggers?
Database trigger are written in database directly and fire on behalf of any transaction like Insert, Update and delete on table automatically. On the other hand we form level trigger are use in forms and fire on any level like item level, row level or on block level on requirement of application. Main difference in database trigger and form level triggers is that database trigger fire automatically and form level trigger fire on user or application requirement.
What is the advantage of stored procedure over the database triggers?
Store procedure are compile one time and stay in database and wait for calling but on the other hand database trigger fire every time when we have to perfume any change in database.
What are cascading of triggers?
Cascading of trigger means if we insert data in one table and that table have trigger on it then trigger fire. And in this trigger there is another table that we are using for insert the data in it and this table has also trigger on it then this trigger also fire. This is called cascading of triggers.
What is Pseudo column?
Pseudo columns are database columns that are using for different purposes in oracle database like ROWNUM, ROWID, SYSDATE, UID, USER, ORA_ROWSCN, SYSTIMESTAMP,
What is Dual and where it can be use?
Dual is a database table owner is sys and reside in data dictionary. It have only one column name DUMMY and one data X. It is normally use for select the values of Pseudo columns.
Can we insert, update, delete, alter and drop DUAL table?
Yes we can Insert, update, delete alter and also drop Dual table in oracle.
If we create a table with name DUAL it can be work same as DUAL?
Yes we create table with same name of DUAL and also it will work like same of dual table.
What are group functions and how many types of group function?
Group functions return the single result on based on many rows. Like count, sum, min, max, avg first, last these functions return one row result based on many rows.
What are cursors and how many types of cursors?
Cursor is a pointer variable in a memory and use for DML operations. Cursor basically is a private SQL memory area it is also use to improve the performance of the database.
There are two types of cursors.
1- Implicit cursor
2- Explicit cursor
Implicit cursor use oracles to manipulate the DML opperations and programmer have no control on this type of cursor. We use sql%notfound and sql%rowcount in implicit cursor. Explicit cursors are created by the programmer and programmer can control it by using these keywords Fetch, Open and close.
Define Oracle cursor attributes.
There are five types of cursors attributes
1- %isopen (Verify whether this cursor is open or not)
2- %found (If cursor fetch the data then %found return true)
3- %notfound (If cursor fetches not data then %notfound return true)
4- %rowcount (It return no. of rows that are in cursor and also give position of record)
5- %bulk_rowcount (%bulk_rowcount is same like %rowcount but it is used in bulk)
How can we pass variable in cursors?
We can pass the variable in cursor by using parameter cursor. Just we give the variable in it like cursor C1 (my_variable number).
What is the CASE statement and where we can use it?
CASE statement is just like IT-THEN-ELSE condition it is normally use when we are using some type of if else condition. When condition is founded true the case statement return the result and no further evaluating of data.
What is INDEX, when and where we can use it?
Index is using for performance tuning and also give us faster data retrieval of record from tables. Index can create on any column in table by default oracle B-Tree index.
Which operator that are not coming in Indexing?
NOT IN operator is not coming in indexing.
How we can get limited rows in SQL?
We can get limited rows in oracle database by using ROWNUM or HAVING clause.
What is the difference between Sub query and Co-related query?
One query contains more than one sub-query. The inner most query run first then second outer then third outer and so on. If we will not use relation on inner query to outer query then this query is called sub-query if we use relation then this query called Correlated query.
Example of Sub Query:
SELECT EMP_NAME, DEPTNO FROM EMP
WHERE EMP_NAME IN (SELECT EMP_NAME FROM DEPT)
Example of Correlated Query:
SELECT EMP_NAME, DEPTNO FROM EMP
WHERE EMP_NAME IN (SELECT EMP_NAME FROM DEPT WHERE EMP.DEPTNO = DEPT.DEPTNO)
What is exception handling and how we can handle the exception in Oracle?
Exception is an error situation which arises during program execution. When an error occurs exception is raised normally execution is stopped and control transfers to exception handling part. Exception handlers are routines written to handle the exception. The exceptions can be internally defined User-defined exception. In oracle we can handle exception by using these statements.
EXCEPTION WHEN
DUP_VAL_ON_INDEX
NOT_LOGGED_ON
NO_DATA_FOUND
TOO_MANY_ROWS
VALUE_ERROR
Can we define more than one exception in one block?
Yes we can define more than one exception in one block in oracle form builder like we will use DUP_VAL_ON_INDEX and NO_DATA_FOUND simultaneously
What is SQL sequence and what are their attributes?
Sequence is an Oracle object that is using for generating the sequence of number. IT=T is normally using for column that have primary key.
“CREATE SEQUENCE TRANS_ID_SEQ
START WITH 1
MAXVALUE 99999999
MINVALUE 1
NOCYCLE
NOCACHE
NOORDER”
What is CYCLE AND NO CYCLE in sequence?
When we use “CYCLE” option in sequence and sequence reaches its MAXVALUE, it will start again from the MINVALUE. That is not good when we are using the sequence for primary key. In “NOCYCLE” option cursor did not start from minimum value again.
Can we design one view on another view?
Yes we can design one view on the other view.
What are aggregate functions in Oracle?
Aggregate function are using in oracle with group by clause and with having clause. Avg, count, max, min, sum,
How can we sort out our data in oracle?
We can sort out or data in oracle by using Order by clause. If we sort our data then we use this Order by Roll_Num AEC and fro descending order we will use Order by Roll_Num Desc.
What is a PL/SQL package and what are the advantages of PL/SQL Packages?
A package is a collection of PL/SQL elements that are grouped together within a special BEGIN-END syntax. A package is a schema object that groups logically related PL/SQL types, items, and subprograms.
Packages usually have two parts, a specification and a body, although sometimes the body is unnecessary. The specification (spec for short) is the interface to your applications; it declares the types, variables, constants, exceptions, cursors, and subprograms available for use. The body fully defines cursors and subprograms, and so implements the spec.
What are the query and how many types of queries?
A database query is some type of syntax that is sent to database and get some data or information from the database. It is some type of communicator that is using for giving something and taking something from database.
· Simple Query
· Advanced Query
· Saved Query
· Cross-project Query
What is the union, intersect and minus operation in oracle?
Create table MY_A
(
My_ID number
)
Table A values: (1, 2, 3)
Create table MY_B
(
My_ID number
)
Table A values: (1, 2, 5)
For UNION:
Select MY_ID from MY_A;
UNION
Select MY_ID from MY_B;
Result: 1, 2, 3,5
For INTERSECT:
Select MY_ID from MY_A;
INTERSECT
Select MY_ID from MY_B;
Result: 1, 2
For MINUS:
Select MY_ID from MY_A;
MINUS
Select MY_ID from MY_B;
Result: 3
What is the difference between UNION and UNION ALL?
In UNION if two rows will match then result come only of two rows but if we use UNION ALL then result will be four rows.
Create table MY_A
(
My_ID number
)
Table A values: (1, 2, 3)
Create table MY_B
(
My_ID number
)
Table B values: (1, 2, 5)
For UNION:
Select MY_ID from MY_A;
UNION
Select MY_ID from MY_B;
Result: 1, 2, 3,5
For UNION ALL:
Select MY_ID from MY_A;
UNION ALL
Select MY_ID from MY_B;
Result: 1,1, 2,2, 3,5
Explain in detail use of OCI in oracle?
OCI is an API that provides functions you can use to access the database server and control SQL execution. OCI supports the data types, calling conventions, syntax, and semantics of the C and C++ programming languages. You compile and link an OCI program much as you would any C or C++ program.
Oracle function can take OUT parameter?
Yes we use OUT parameter in function.
In form Parameter can we define default value?
Yes you can define initial value in form parameter.
What is the difference between NO_DATA_FOUND and %NOTFOUND?
“NO_DATA_FOUND” is a system defined exception. It is generated when no record found in implicit cursor. “%NOTFOUND” is used in cursor. If cursor returns no row then %NOTFOUND returns true and if returns row then %NOTFOUND is false.
Write a statement to find out the no. of rows in oracle?
Select count(*) from emp;
Which function is use for display the numeric figure in words?
SELECT TO_CHAR(TO_DATE(123,'J'),'JSP') to_words FROM dual;
What is the difference between WHERE clause and HAVING clause?
WHERE clause use in simple select statement on the other hand HAVING clause use in group function statement like.
Select emp_name from WHEER dept_code=123;
Select emp_name from emp HAVING count(emp_cod) > 2;
Write a difference between SUBSTR and INSTR function?
SUBSTR provide some portion of string like from one word to 5th word and INSTR gives us location of that particular word.
What are the components of Physical database structure of Oracle Database?ORACLE database is comprised of three types of files. One or more Data files, two are more Redo Log files, and one or more Control files.
What are the components of Logical database structure of ORACLE database?
Tablespaces and the Database’s Schema Objects.
What is a Tablespace?
A database is divided into Logical Storage Unit called tablespaces. A tablespace is used to grouped related logical structures together.
What is SYSTEM tablespace and When is it Created?
Every ORACLE database contains a table space named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.
Explain the relationship among Database, Tablespace and Data file
Each databases logically divided into one or more tablespaces One or more data files are explicitly created for each tablespace.
What is schema?
A schema is collection of database objects of a User.
What are Schema Objects ?
Schema objects are the logical structures that directly refer to the database’s data. Schema objects include tables, views, sequences, synonyms, indexes, clusters, database triggers, procedures, functions packages and database links.
Can objects of the same Schema reside in different tablespaces.?
Yes.
Can a Tablespace hold objects from different Schemes ?
Yes.
what is Table ?
A table is the basic unit of data storage in an ORACLE database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.
What is a View ?
A view is a virtual table. Every view has a Query attached to it. (The Query is a SELECT statement that identifies the columns and rows of the table(s) the view uses.)
Do View contain Data ?
Views do not contain or store data.
Can a View based on another View ?
Yes.
What are the advantages of Views ?
Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
Hide data complexity.
Simplify commands for the user.
Present the data in a different perpecetive from that of the base table.
Store complex queries.
What is a Sequence ?
A sequence generates a serial list of unique numbers for numerical columns of a database’s tables.
What is a Synonym ?
A synonym is an alias for a table, view, sequence or program unit.
What are the type of Synonyms?
There are two types of Synonyms Private and Public.
What is a Private Synonyms ?
A Private Synonyms can be accessed only by the owner.
What is a Public Synonyms ?
A Public synonyms can be accessed by any user on the database.
What are synonyms used for ?
Synonyms are used to: Mask the real name and owner of an object.
Provide public access to an object Provide location transparency for tables, views or program units of a remote database. Simplify the SQL statements for database users.
What is an Index ?
An Index is an optional structure associated with a table to have direct access to rows, which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.
How are Indexes Update ?
Indexes are automatically maintained and used by ORACLE. Changes to table data are automatically incorporated into all relevant indexes.
What are Clusters?
Clusters are groups of one or more tables physically stores together to share common columns and are often used together.
What is cluster Key?
The related columns of the tables in a cluster are called the Cluster Key.
What is Index Cluster ?
A Cluster with an index on the Cluster Key.
What is Hash Cluster ?
A row is stored in a hash cluster based on the result of applying a hash function to the row’s cluster key value. All rows with the same hash key value are stores together on disk.
When can Hash Cluster used ?
Hash clusters are better choice when a table is often queried with equality queries. For such queries the specified cluster key value is hashed. The resulting hash key value points directly to the area on disk that stores the specified rows.
What is Database Link ?
A database link is a named object that describes a “path” from one database to another.
What are the types of Database Links ?
Private Database Link, Public Database Link & Network Database Link.
What is Private Database Link ?
Private database link is created on behalf of a specific user. A private database link can be used only when the owner of the link specifies a global object name in a SQL statement or in the definition of the owner’s views or procedures.
What is Public Database Link ?
Public database link is created for the special user group PUBLIC. A public database link can be used when any user in the associated database specifies a global object name in a SQL statement or object definition.
What is Network Database link ?
Network database link is created and managed by a network domain service. A network database link can be used when any user of any database in the network specifies a global object name in a SQL statement or object definition.
What is Data Block ?
ORACLE database’s data is stored in data blocks. One data block corresponds to a specific number of bytes of physical database space on disk.
How to define Data Block size ?
A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE datablocks. Block size is specified in INIT.ORA file and can’t be changed latter.
What is Row Chaining ?
In Circumstances, all of the data for a row in a table may not be able to fit in the same data block. When this occurs , the data for the row is stored in a chain of data block (one or more) reserved for that segment.
What is an Extent ?
An Extent is a specific number of contiguous data blocks, obtained in a single allocation, used to store a specific type of information.
What is a Segment ?
A segment is a set of extents allocated for a certain logical structure.
What are the different type of Segments ?
Data Segment, Index Segment, Rollback Segment and Temporary Segment.
What is a Data Segment ?
Each Non-clustered table has a data segment. All of the table’s data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster’s data segment.
What is an Index Segment ?
Each Index has an Index segment that stores all of its data.
What is Rollback Segment ?
A Database contains one or more Rollback Segments to temporarily store “undo” information.
What are the uses of Rollback Segment ?
Rollback Segments are used :
To generate read-consistent database information during database recovery to rollback uncommitted transactions for users.
What is a Temporary Segment ?
Temporary segments are created by ORACLE when a SQL statement needs a temporary work area to complete execution. When the statement finishes execution, the temporary segment extents are released to the system for future use.
What is a Data File ?
Every ORACLE database has one or more physical data files. A database’s data files contain all the database data. The data of logical database structures such as tables and indexes is physically stored in the data files allocated for a database.
What are the Characteristics of Data Files ?
A data file can be associated with only one database. Once created a data file can’t change size. One or more data files form a logical unit of database storage called a table space.
What is a Redo Log?
The set of Redo Log files for a database is collectively known as the database’s redo log.
What is the function of Redo Log ?
The Primary function of the redo log is to record all changes made to data.
What is the use of Redo Log Information ?
The Information in a redo log file is used only to recover the database from a system or media failure prevents database data from being written to a database’s data files.
What does a Control file Contain ?
A Control file records the physical structure of the database. It contains the following information.
Database Name
Names and locations of a database’s files and redolog files.
Time stamp of database creation.
What is the use of Control File ?
When an instance of an ORACLE database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.
What is a Data Dictionary ?
The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database. It stores information about both the logical and physical structure of the database, the valid users of an ORACLE database, integrity constraints defined for tables in the database and space allocated for a schema object and how much of it is being used.
What is an Integrity Constrains ?
An integrity constraint is a declarative way to define a business rule for a column of a table.
Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ?
No.
Describe the different type of Integrity Constraints supported by ORACLE ?
NOT NULL Constraint - Disallows NULLs in a table’s column.
UNIQUE Constraint – Disallows duplicate values in a column or set of columns.
PRIMARY KEY Constraint - Disallows duplicate values and NULLs in a column or set of columns.
FOREIGN KEY Constrain - Require each value in a column or set of columns match a value in a related table’s UNIQUE or PRIMARY KEY.
CHECK Constraint - Disallows values that do not satisfy the logical expression of the constraint.
What is difference between UNIQUE constraint and PRIMARY KEY constraint ?
A column defined as UNIQUE can contain NULLs while a column defined as PRIMARY KEY can’t contain Nulls.
Describe Referential Integrity ?
A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column of a related table (the referenced value). It also specifies the type of data manipulation allowed on referenced data and the action to be performed on dependent data as a result of any action on referenced data.
What are the Referential actions supported by FOREIGN KEY integrity constraint ?
UPDATE and DELETE Restrict – A referential integrity rule that disallows the update or deletion of referenced data.
DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted.
What is self-referential integrity constraint ?
If a foreign key reference a parent key of the same table is called self-referential integrity constraint.
What are the Limitations of a CHECK Constraint ?
The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can’t contain subqueries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or the pseudo columns LEVEL or ROWNUM.
What is the maximum number of CHECK constraints that can be defined on a column ?
No Limit.
61. What constitute an ORACLE Instance ?
SGA and ORACLE background processes constitute an ORACLE instance. (or) Combination of memory
structure and background process.
62. What is SGA ?
The System Global Area (SGA) is a shared memory region allocated by ORACLE that contains data and
control information for one ORACLE instance.
63. What are the components of SGA ?
Database buffers, Redo Log Buffer the Shared Pool and Cursors.
64. What do Database Buffers contain ?
Database buffers store the most recently used blocks of database data. It can also contain modified
data that has not yet been permanently written to disk.
65. What do Redo Log Buffers contain ?
Redo Log Buffer stores redo entries a log of changes made to the database.
66. What is Shared Pool ?
Shared Pool is a portion of the SGA that contains shared memory constructs such as shared SQL areas.
67. What is Shared SQL Area ?
A Shared SQL area is required to process every unique SQL statement submitted to a database and
contains information such as the parse tree and execution plan for the corresponding statement.
68. What is Cursor ?
A Cursor is a handle ( a name or pointer) for the memory associated with a specific statement.
69. What is PGA ?
Program Global Area (PGA) is a memory buffer that contains data and control information for a server
process.
70. What is User Process ?
A user process is created and maintained to execute the software code of an application program. It
is a shadow process created automatically to facilitate communication between the user and the
server process.
71. What is Server Process ?
Server Process handle requests from connected user process. A server process is in charge of
communicating with the user process and interacting with ORACLE carry out requests of the associated
user process.
72. What are the two types of Server Configurations ?
Dedicated Server Configuration and Multi-threaded Server Configuration.
73. What is Dedicated Server Configuration ?
In a Dedicated Server Configuration a Server Process handles requests for a Single User Process.
74. What is a Multi-threaded Server Configuration ?
In a Multi-threaded Server Configuration many user processes share a group of server process.
75. What is a Parallel Server option in ORACLE ?
A configuration for loosely coupled systems where multiple instance share a single physical database
is called Parallel Server.
76. Name the ORACLE Background Process ?
DBWR – Database Writer.
LGWR – Log Writer
CKPT – Check Point
SMON – System Monitor
PMON – Process Monitor
ARCH – Archiver
RECO – Recover
Dnnn – Dispatcher, and
LCKn – Lock
Snnn – Server.
77. What Does DBWR do ?
Database writer writes modified blocks from the database buffer cache to the data files.
78.When Does DBWR write to the database ?
DBWR writes when more data needs to be read into the SGA and too few database buffers are free. The
least recently used data is written to the data files first. DBWR also writes when CheckPoint
occurs.
79. What does LGWR do ?
Log Writer (LGWR) writes redo log entries generated in the redo log buffer of the SGA to on-line
Redo Log File.
80. When does LGWR write to the database?
LGWR writes redo log entries into an on-line redo log file when transactions commit and the log
buffer files are full.
81. What is the function of checkpoint CKPT)?
The Checkpoint (CKPT) process is responsible for signaling DBWR at checkpoints and updating all the
data files and control files of the database.
82. What are the functions of SMON ?
System Monitor (SMON) performs instance recovery at instance start-up. In a multiple instance system
(one that uses the Parallel Server), SMON of one instance can also perform instance recovery for
other instance that have failed SMON also cleans up temporary segments that are no longer in use and
recovers dead transactions skipped during crash and instance recovery because of file-read or
off-line errors. These transactions are eventually recovered by SMON when the tablespace or file is
brought back on-line SMON also coalesces free extents within the database to make free space
contiguous and easier to allocate.
83. What are functions of PMON ?
Process Monitor (PMON) performs process recovery when a user process fails PMON is responsible for
cleaning up the cache and Freeing resources that the process was using PMON also checks on
dispatcher and server processes and restarts them if they have failed.
84. What is the function of ARCH ?
Archiver (ARCH) copies the on-line redo log files to archival storage when they are full. ARCH is
active only when a database’s redo log is used in ARCHIVELOG mode.
85. What is function of RECO ?
RECOver (RECO) is used to resolve distributed transactions that are pending due to a network or
system failure in a distributed database. At timed intervals,the local RECO attempts to connect to
remote databases and automatically complete the commit or rollback of the local portion of any
pending distributed transactions.
86. What is the function of Dispatcher (Dnnn) ?
Dispatcher (Dnnn) process is responsible for routing requests from connected user processes to
available shared server processes and returning the responses back to the appropriate user
processes.
87. How many Dispatcher Processes are created ?
Atleast one Dispatcher process is created for every communication protocol in use.
88. What is the function of Lock (LCKn) Process ?
Lock (LCKn) are used for inter-instance locking when the ORACLE Parallel Server option is used.
89. What is the maximum number of Lock Processes used ?
Though a single LCK process is sufficient for most Parallel Server systems
upto Ten Locks (LCK0,….LCK9) are used for inter-instance locking.
DATA ACCESS
90. Define Transaction ?
A Transaction is a logical unit of work that comprises one or more SQL statements executed by a
single user.
91. When does a Transaction end ?
When it is committed or Rollbacked.
92. What does COMMIT do ?
COMMIT makes permanent the changes resulting from all SQL statements in the transaction. The changes
made by the SQL statements of a transaction become visible to other user sessions transactions that
start only after transaction is committed.
93. What does ROLLBACK do ?
ROLLBACK retracts any of the changes resulting from the SQL statements in the transaction.
94. What is SAVE POINT ?
For long transactions that contain many SQL statements, intermediate markers or savepoints can be
declared which can be used to divide a transaction into smaller parts. This allows the option of
later rolling back all work performed from the current point in the transaction to a declared
savepoint within the transaction.
95. What is Read-Only Transaction ?
A Read-Only transaction ensures that the results of each query executed in the transaction are
consistant with respect to the same point in time.
96. What is the function of Optimizer ?
The goal of the optimizer is to choose the most efficient way to execute a SQL statement.
97. What is Execution Plan ?
The combinations of the steps the optimizer chooses to execute a statement is called an execution
plan.
98. What are the different approaches used by Optimizer in choosing an execution plan ?
Rule-based and Cost-based.
99. What are the factors that affect OPTIMIZER in choosing an Optimization approach ?
The OPTIMIZER_MODE initialization parameter Statistics in the Data Dictionary the OPTIMIZER_GOAL
parameter of the ALTER SESSION command hints in the statement.
100. What are the values that can be specified for OPTIMIZER MODE Parameter ?
COST and RULE.
101. Will the Optimizer always use COST-based approach if OPTIMIZER_MODE is set to “Cost’?
Presence of statistics in the data dictionary for atleast one of the tables accessed by the SQL
statements is necessary for the OPTIMIZER to use COST-based approach. Otherwise OPTIMIZER chooses
RULE-based approach.
102. What is the effect of setting the value of OPTIMIZER_MODE to ‘RULE’ ?
This value causes the optimizer to choose the rule_based approach for all SQL statements issued to
the instance regardless of the presence of statistics.
103. What are the values that can be specified for OPTIMIZER_GOAL parameter of the ALTER SESSION
Command ?
CHOOSE,ALL_ROWS,FIRST_ROWS and RULE.
104. What is the effect of setting the value “CHOOSE” for OPTIMIZER_GOAL, parameter of the ALTER
SESSION Command ?
The Optimizer chooses Cost_based approach and optimizes with the goal of best throughput if
statistics for atleast one of the tables accessed by the SQL statement exist in the data dictionary.
Otherwise the OPTIMIZER chooses RULE_based approach.
105. What is the effect of setting the value “ALL_ROWS” for OPTIMIZER_GOAL parameter of the ALTER
SESSION command ?
This value causes the optimizer to the cost-based approach for all SQL statements in the session
regardless of the presence of statistics and to optimize with a goal of best throughput.
106. What is the effect of setting the value ‘FIRST_ROWS’ for OPTIMIZER_GOAL parameter of the ALTER
SESSION command ?
This value causes the optimizer to use the cost-based approach for all SQL statements in the session
regardless of the presence of statistics and to optimize with a goal of best response time.
107. What is the effect of setting the ‘RULE’ for OPTIMIER_GOAL parameter of the ALTER SESSION
Command ?
This value causes the optimizer to choose the rule-based approach for all SQL statements in a
session regardless of the presence of statistics.
108. What is RULE-based approach to optimization ?
Choosing an executing planbased on the access paths available and the ranks of these access paths.
109. What is COST-based approach to optimization ?
Considering available access paths and determining the most efficient execution plan based on
statistics in the data dictionary for the tables accessed by the statement and their associated
clusters and indexes.
PROGRAMMATIC CONSTRUCTS
110. What are the different types of PL/SQL program units that can be defined and stored in ORACLE
database ?
Procedures and Functions,Packages and Database Triggers.
111. What is a Procedure ?
A Procedure consist of a set of SQL and PL/SQL statements that are grouped together as a unit to
solve a specific problem or perform a set of related tasks.
112. What is difference between Procedures and Functions ?
A Function returns a value to the caller where as a Procedure does not.
113. What is a Package ?
A Package is a collection of related procedures, functions, variables and other package constructs
together as a unit in the database.
114. What are the advantages of having a Package ?
Increased functionality (for example,global package variables can be declared and used by any
proecdure in the package) and performance (for example all objects of the package are parsed
compiled, and loaded into memory once)
115. What is Database Trigger ?
A Database Trigger is procedure (set of SQL and PL/SQL statements) that is automatically executed as
a result of an insert in,update to, or delete from a table.
116. What are the uses of Database Trigger ?
Database triggers can be used to automatic data generation, audit data modifications, enforce
complex Integrity constraints, and customize complex security authorizations.
117. What are the differences between Database Trigger and Integrity constraints ?
A declarative integrity constraint is a statement about the database that is always true. A
constraint applies to existing data in the table and any statement that manipulates the table.
A trigger does not apply to data loaded before the definition of the trigger, therefore, it does not
guarantee all data in a table conforms to the rules established by an associated trigger.
A trigger can be used to enforce transitional constraints where as a declarative integrity
constraint cannot be used.
DATABASE SECURITY
118. What are Roles ?
Roles are named groups of related privileges that are granted to users or other roles.
119. What are the use of Roles ?
REDUCED GRANTING OF PRIVILEGES – Rather than explicitly granting the same set of privileges to many
users a database administrator can grant the privileges for a group of related users granted to a
role and then grant only the role to each member of the group.
DYNAMIC PRIVILEGE MANAGEMENT – When the privileges of a group must change, only the privileges of
the role need to be modified. The security domains of all users granted the group’s role
automatically reflect the changes made to the role.
SELECTIVE AVAILABILITY OF PRIVILEGES – The roles granted to a user can be selectively enable
(available for use) or disabled (not available for use). This allows specific control of a user’s
privileges in any given situation.
APPLICATION AWARENESS – A database application can be designed to automatically enable and disable
selective roles when a user attempts to use the application.
120. How to prevent unauthorized use of privileges granted to a Role ?
By creating a Role with a password.
121. What is default tablespace ?
The Tablespace to contain schema objects created without specifying a tablespace name.
122. What is Tablespace Quota ?
The collective amount of disk space available to the objects in a schema on a particular tablespace.
123. What is a profile ?
Each database user is assigned a Profile that specifies limitations on various system resources
available to the user.
124. What are the system resources that can be controlled through Profile ?
The number of concurrent sessions the user can establish the CPU processing time available to the
user’s session the CPU processing time available to a single call to ORACLE made by a SQL statement
the amount of logical I/O available to the user’s session the amout of logical I/O available to a
single call to ORACLE made by a SQL statement the allowed amount of idle time for the user’s session
the allowed amount of connect time for the user’s session.
125. What is Auditing ?
Monitoring of user access to aid in the investigation of database use.
126. What are the different Levels of Auditing ?
Statement Auditing, Privilege Auditing and Object Auditing.
127. What is Statement Auditing ?
Statement auditing is the auditing of the powerful system privileges without regard to specifically
named objects.
128. What is Privilege Auditing ?
Privilege auditing is the auditing of the use of powerful system privileges without regard to
specifically named objects.
129. What is Object Auditing ?
Object auditing is the auditing of accesses to specific schema objects without regard to user.
DISTRIBUTED PROCESSING AND DISTRIBUTED DATABASES
130. What is Distributed database ?
A distributed database is a network of databases managed by multiple database servers that appears
to a user as single logical database. The data of all databases in the distributed database can be
simultaneously accessed and modified.
131. What is Two-Phase Commit ?
Two-phase commit is mechanism that guarantees a distributed transaction either commits on all
involved nodes or rolls back on all involved nodes to maintain data consistency across the global
distributed database. It has two phase, a Prepare Phase and a Commit Phase.
132. Describe two phases of Two-phase commit ?
Prepare phase – The global coordinator (initiating node) ask a participants to prepare (to promise
to commit or rollback the transaction, even if there is a failure)
Commit – Phase – If all participants respond to the coordinator that they are prepared, the
coordinator asks all nodes to commit the transaction, if all participants cannot prepare, the
coordinator asks all nodes to roll back the transaction.
133. What is the mechanism provided by ORACLE for table replication ?
Snapshots and SNAPSHOT LOGs
134. What is a SNAPSHOT ?
Snapshots are read-only copies of a master table located on a remote node which is periodically
refreshed to reflect changes made to the master table.
135. What is a SNAPSHOT LOG ?
A snapshot log is a table in the master database that is associated with the master table. ORACLE
uses a snapshot log to track the rows that have been updated in the master table. Snapshot logs are
used in updating the snapshots based on the master table.
136. What is a SQL * NET?
SQL *NET is ORACLE’s mechanism for interfacing with the communication protocols used by the networks
that facilitate distributed processing and distributed databases. It is used in Clint-Server and
Server-Server communications.
DATABASE OPERATION, BACKUP AND RECOVERY
137. What are the steps involved in Database Startup ?
Start an instance, Mount the Database and Open the Database.
138. What are the steps involved in Database Shutdown ?
Close the Database, Dismount the Database and Shutdown the Instance.
139. What is Restricted Mode of Instance Startup ?
An instance can be started in (or later altered to be in) restricted mode so that when the database
is open connections are limited only to those whose user accounts have been granted the RESTRICTED
SESSION system privilege.
140. What are the different modes of mounting a Database with the Parallel Server ?
Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that
Instance can mount the database.
Parallel Mode If the first instance that mounts a database is started in parallel mode, other
instances that are started in parallel mode can also mount the database.
141. What is Full Backup ?
A full backup is an operating system backup of all data files, on-line redo log files and control
file that constitute ORACLE database and the parameter.
142. Can Full Backup be performed when the database is open ?
No.
143. What is Partial Backup ?
A Partial Backup is any operating system backup short of a full backup, taken while the database is
open or shut down.
144.WhatisOn-lineRedoLog?
The On-line Redo Log is a set of tow or more on-line redo files that record all committed changes
made to the database. Whenever a transaction is committed, the corresponding redo entries
temporarily stores in redo log buffers of the SGA are written to an on-line redo log file by the
background process LGWR. The on-line redo log files are used in cyclical fashion.
145. What is Mirrored on-line Redo Log ?
A mirrored on-line redo log consists of copies of on-line redo log files physically located on
separate disks, changes made to one member of the group are made to all members.
146. What is Archived Redo Log ?
Archived Redo Log consists of Redo Log files that have archived before being reused.
147. What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO
ARCHIVELOG mode ?
Complete database recovery from disk failure is possible only in ARCHIVELOG mode.
Online database backup is possible only in ARCHIVELOG mode.
148. What is Log Switch ?
The point at which ORACLE ends writing to one online redo log file and begins writing to another is
called a log switch.
149. What are the steps involved in Instance Recovery ?
R_olling forward to recover data that has not been recorded in data files, yet has been recorded in
the on-line redo log, including the contents of rollback segments.
Rolling back transactions that have been explicitly rolled back or have not been committed as
indicated by the rollback segments regenerated in step a.
Releasing any resources (locks) held by transactions in process at the time of the failure.
Resolving any pending distributed transactions undergoing a two-phase commit at the time of the
instance failure.
1. What is a Database instance ? Explain
A database instance (Server) is a set of memory structure and background processes that access a set
of database files.
The process can be shared by all users.
The memory structure that are used to store most queried data from database. This helps up to
improve database performance by decreasing the amount of I/O performed against data file.
2. What is Parallel Server ?
Multiple instances accessing the same database (Only In Multi-CPU environments)
3. What is a Schema ?
The set of objects owned by user account is called the schema.
4. What is an Index ? How it is implemented in Oracle Database ?
An index is a database structure used by the server to have direct access of a row in a table.
An index is automatically created when a unique of primary key constraint clause is specified in
create table comman (Ver 7.0)
5. What is clusters ?
Group of tables physically stored together because they share common columns and are often used
together is called Cluster.
6. What is a cluster Key ?
The related columns of the tables are called the cluster key. The cluster key is indexed using a
cluster index and its value is stored only once for multiple tables in the cluster.
7. What are the basic element of Base configuration of an oracle Database ?
It consists of
one or more data files.
one or more control files.
two or more redo log files.
The Database contains
multiple users/schemas
one or more rollback segments
one or more tablespaces
Data dictionary tables
User objects (table,indexes,views etc.,)
The server that access the database consists of
SGA (Database buffer, Dictionary Cache Buffers, Redo log buffers, Shared SQL pool)
SMON (System MONito)
PMON (Process MONitor)
LGWR (LoG Write)
DBWR (Data Base Write)
ARCH (ARCHiver)
CKPT (Check Point)
RECO
Dispatcher
User Process with associated PGS
8. What is a deadlock ? Explain.
Two processes wating to update the rows of a table which are locked by the other process then
deadlock arises.
In a database environment this will often happen because of not issuing proper row lock commands.
Poor design of front-end application may cause this situation and the performance of server will
reduce drastically.
These locks will be released automatically when a commit/rollback operation performed or any one of
this processes being killed externally.
MEMORY MANAGEMENT
9. What is SGA ? How it is different from Ver 6.0 and Ver 7.0 ?
The System Global Area in a Oracle database is the area in memory to facilitates the transfer of
information between users. It holds the most recently requested structural information between
users. It holds the most recently requested structural information about the database.
The structure is Database buffers, Dictionary cache, Redo Log Buffer and Shared SQL pool (ver 7.0
only) area.
10. What is a Shared SQL pool ?
The data dictionary cache is stored in an area in SGA called the Shared SQL Pool. This will allow
sharing of parsed SQL statements among concurrent users.
11. What is mean by Program Global Area (PGA) ?
It is area in memory that is used by a Single Oracle User Process.
12. What is a data segment ?
Data segment are the physical areas within a database block in which the data associated with tables
and clusters are stored.
13. What are the factors causing the reparsing of SQL statements in SGA?
Due to insufficient Shared SQL pool size.
Monitor the ratio of the reloads takes place while executing SQL statements. If the ratio is greater
than 1 then increase the SHARED_POOL_SIZE.
LOGICAL & PHYSICAL ARCHITECTURE OF DATABASE
14. What is Database Buffers ?
Database buffers are cache in the SGA used to hold the data blocks that are read from the data
segments in the database such as tables, indexes and clusters DB_BLOCK_BUFFERS parameter in INIT.ORA
decides the size.
15. What is dictionary cache ?
Dictionary cache is information about the databse objects stored in a data dictionary table.
16. What is meant by recursive hints ?
Number of times processes repeatedly query the dictionary table is called recursive hints. It is due
to the data dictionary cache is too small. By increasing the SHARED_POOL_SIZE parameter we can
optimize the size of Data Dictionary Cache.
17. What is meant by redo log buffer ?
Change made to entries are written to the on-line redo log files. So that they can be used in roll
forward operations during database recoveries. Before writing them into the redo log files, they
will first brought to redo log buffers in SGA and LGWR will write into files frequently.
LOG_BUFFER parameter will decide the size.
18. How will you swap objects into a different table space for an existing database ?
Export the user
Perform import using the command imp system/manager file=export.dmp indexfile=newrite.sql. This will
create all definitions into newfile.sql.
Drop necessary objects.
Run the script newfile.sql after altering the tablespaces.
Import from the backup for the necessary objects.
19. List the Optional Flexible Architecture (OFA) of Oracle database ? or How can we organise the
tablespaces in Oracle database to have maximum performance ?
SYSTEM – Data dictionary tables.
DATA – Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES – Indexes for Standard operational tables.
INDEXES1 – Indexes of static tables used for standard operations.
TOOLS – Tools table.
TOOLS1 – Indexes for tools table.
RBS – Standard Operations Rollback Segments,
RBS1,RBS2 – Additional/Special Rollback segments.
TEMP – Temporary purpose tablespace
TEMP_USER – Temporary tablespace for users.
USERS – User tablespace.
20. How will you force database to use particular rollback segment ?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
21. What is meant by free extent ?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its
extents are reallocated and are marked as free.
22. How free extents are managed in Ver 6.0 and Ver 7.0 ?
Free extents cannot be merged together in Ver 6.0.
Free extents are periodically coalesces with the neighboring free extent in
Ver 7.0
23.Which parameter in Storage clause will reduce no. of rows per block?
PCTFREE parameter
Row size also reduces no of rows per block.
24. What is the significance of having storage clause ?
We can plan the storage for a table as how much initial extents are required, how much can be
extended next, how much % should leave free for managing row updations etc.,
25. How does Space allocation table place within a block ?
Each block contains entries as follows
Fixied block header
Variable block header
Row Header,row date (multiple rows may exists)
PCTEREE (% of free space for row updation in future)
26. What is the role of PCTFREE parameter is Storage clause ?
This is used to reserve certain amount of space in a block for expansion of rows.
27. What is the OPTIMAL parameter ?
It is used to set the optimal length of a rollback segment.
28. What is the functionality of SYSTEM table space ?
To manage the database level transactions such as modifications of the data dictionary table that
record information about the free space usage.
29. How will you create multiple rollback segments in a database ?
Create a database which implicitly creates a SYSTEM Rollback Segment in a SYSTEM tablespace.
Create a Second Rollback Segment name R0 in the SYSTEM tablespace.
Make new rollback segment available (After shutdown, modify init.ora file and Start database)
Create other tablespaces (RBS) for rollback segments.
Deactivate Rollback Segment R0 and activate the newly created rollback segments.
30. How the space utilisation takes place within rollback segments ?
It will try to fit the transaction in a cyclic fashion to all existing extents. Once it found an
extent is in use then it forced to acquire a new extent (No. of extents is based on the optimal
size)
31. Why query fails sometimes ?
Rollback segment dynamically extent to handle larger transactions entry loads.
A single transaction may wipeout all avaliable free space in the Rollback Segment Tablespace. This
prevents other user using Rollback segments.
32. How will you monitor the space allocation ?
By quering DBA_SEGMENT table/view.
33. How will you monitor rollback segment status ?
Querying the DBA_ROLLBACK_SEGS view
IN USE – Rollback Segment is on-line.
AVAILABLE – Rollback Segment available but not on-line.
OFF-LINE – Rollback Segment off-line
INVALID – Rollback Segment Dropped.
NEEDS RECOVERY – Contains data but need recovery or corupted.
PARTLY AVAILABLE – Contains data from an unresolved transaction involving a distributed database.
34. List the sequence of events when a large transaction that exceeds beyond its optimal value when
an entry wraps and causes the rollback segment to expand into another extend.
Transaction Begins.
An entry is made in the RES header for new transactions entry
Transaction acquires blocks in an extent of RBS
The entry attempts to wrap into second extent. None is available, so that the RBS must extent.
The RBS checks to see if it is part of its OPTIMAL size.
RBS chooses its oldest inactive segment.
Oldest inactive segment is eliminated.
RBS extents
The Data dictionary table for space management are updated.
Transaction Completes.
35. How can we plan storage for very large tables ?
Limit the number of extents in the table
Separate Table from its indexes.
Allocate Sufficient temporary storage.
36. How will you estimate the space required by a non-clustered tables?
Calculate the total header size
Calculate the available dataspace per data block
Calculate the combined column lengths of the average row
Calculate the total average row size.
Calculate the average number rows that can fit in a block
Calculate the number of blocks and bytes required for the table.
After arriving the calculation, add 10 % additional space to calculate the initial extent size for a
working table.
37. It is possible to use raw devices as data files and what is the advantages over file. system
files ?
Yes.
The advantages over file system files.
I/O will be improved because Oracle is bye-passing the kernnel which writing into disk.
Disk Corruption will be very less.
38. What is a Control file ?
Database’s overall physical architecture is maintained in a file called control file. It will be
used to maintain internal consistency and guide recovery operations. Multiple copies of control
files are advisable.
39. How to implement the multiple control files for an existing database ?
Shutdown the databse
Copy one of the existing control file to new location
Edit Config ora file by adding new control file.name
Restart the database.
40. What is meant by Redo Log file mirrorring ? How it can be achieved?
Process of having a copy of redo log files is called mirroring.
This can be achieved by creating group of log files together, so that LGWR will automatically writes
them to all the members of the current on-line redo log group. If any one group fails then database
automatically switch over to next group. It degrades performance.
41. What is advantage of having disk shadowing/ Mirroring ?
Shadow set of disks save as a backup in the event of disk failure. In most Operating System if any
disk failure occurs it automatically switchover to place of failed disk.
Improved performance because most OS support volume shadowing can direct file I/O request to use the
shadow set of files instead of the main set of files. This reduces I/O load on the main set of
disks.
42. What is use of Rollback Segments In Database ?
They allow the database to maintain read consistency between multiple transactions.
43. What is a Rollback segment entry ?
It is the set of before image data blocks that contain rows that are modified by a transaction.
Each Rollback Segment entry must be completed within one rollback segment.
A single rollback segment can have multiple rollback segment entries.
44. What is hit ratio ?
It is a measure of well the data cache buffer is handling requests for data.
Hit Ratio = (Logical Reads – Physical Reads – Hits Misses)/ Logical Reads.
45. When will be a segment released ?
When Segment is dropped.
When Shrink (RBS only)
When truncated (TRUNCATE used with drop storage option)
46. What are disadvanteges of having raw devices ?
We should depend on export/import utility for backup/recovery (fully reliable)
The tar command cannot be used for physical file backup, instead we can use dd command which is less
flexible and has limited recoveries.
47. List the factors that can affect the accuracy of the estimations ?
The space used transaction entries and deleted records does not become free immediately after
completion due to delayed cleanout.
Trailling nulls and length bytes are not stored.
Inserts of, updates to and deletes of rows as well as columns larger than a single datablock, can
cause fragmentation an chained row pieces.
DATABASE SECURITY & ADMINISTRATION
48. What is user Account in Oracle database ?
An user account is not a physical structure in Database but it is having important relationship to
the objects in the database and will be having certain privileges.
49. How will you enforce security using stored procedures ?
Don’t grant user access directly to tables within the application.
Instead grant the ability to access the procedures that access the tables.
When procedure executed it will execute the privilege of procedures owner. Users cannot access
tables except via the procedure.
50. What are the dictionary tables used to monitor a database spaces ?
DBA_FREE_SPACE
DBA_SEGMENTS
DBA_DATA_FILES..
Data Base Administration
51. What are the responsibilities of a Database Administrator ?
Installing and upgrading the Oracle Server and application tools.
Allocating system storage and planning future storage requirements for the database system.
Managing primary database structures (tablespaces)
Managing primary objects (table, views, indexes)
Enrolling users and maintaining system security.
Ensuring compliance with Oracle license agreement
Controlling and monitoring user access to the database.
Monitoring and optimising the performance of the database.
Planning for backup and recovery of database information.
Maintain archived data on tape
Backing up and restoring the database.
Contacting Oracle Corporation for technical support.
52. What are the roles and user accounts created automatically with the database ?
DBA – role Contains all database system privileges.
SYS user account – The DBA role will be assigned to this account. All of the basetables and views
for the database’s dictionary are store in this schema and are manipulated only by ORACLE.
SYSTEM user account – It has all the system privileges for the database and additional tables and
views that display administrative information and internal tables and views used by oracle tools are
created using this username.
54. What are the database administrators utilities available ?
SQL * DBA – This allows DBA to monitor and control an ORACLE database.
SQL * Loader – It loads data from standard operating system files (Flat files) into ORACLE database
tables.
Export (EXP) and Import (imp) utilities allow you to move existing data in ORACLE format to and from
ORACLE database.
55. What are the minimum parameters should exist in the parameter file (init.ora) ?
DB NAME – Must set to a text string of no more than 8 characters and it will be stored inside the
datafiles, redo log files and control files and control file while database creation.
DB_DOMAIN – It is string that specifies the network domain where the database is created. The global
database name is identified by setting these parameters (DB_NAME & DB_DOMAIN)
CONTORL FILES – List of control filenames of the database. If name is not mentioned then default
name will be used.
DB_BLOCK_BUFFERS – To determine the no of buffers in the buffer cache in SGA.
PROCESSES – To determine number of operating system processes that can be connected to ORACLE
concurrently. The value should be 5 (background process) and additional 1 for each user.
ROLLBACK_SEGMENTS – List of rollback segments an ORACLE instance acquires at database startup.
Also optionally LICENSE_MAX_SESSIONS,LICENSE_SESSION_WARNING and LICENSE_MAX_USERS.
56. What is a trace file and how is it created ?
Each server and background process can write an associated trace file. When an internal error is
detected by a process or user process, it dumps information about the error to its trace. This can
be used for tuning the database.
57. What are roles ? How can we implement roles ?
Roles are the easiest way to grant and manage common privileges needed by different groups of
database users.
Creating roles and assigning provies to roles.
Assign each role to group of users. This will simplify the job of assigning privileges to individual
users.
58. What are the steps to switch a database’s archiving mode between NO ARCHIVELOG and ARCHIVELOG
mode ?
1. Shutdown the database instance.
2. Backup the database
3. Perform any operating system specific steps (optional)
4. Start up a new instance and mount but do not open the database.
5. Switch the database’s archiving mode.
59. How can you enable automatic archiving ?
Shut the database
Backup the database
Modify/Include LOG_ARCHIVE_START_TRUE in init.ora file.
Start up the database.
60. How can we specify the Archived log file name format and destination ?
By setting the following values in init.ora file.
LOG_ARCHIVE_FORMAT = arch %S/s/T/tarc (%S – Log sequence number and is zero left paded, %s – Log
sequence number not padded. %T – Thread number lef-zero-paded and %t – Thread number not padded).
The file name created is arch 0001 are if %S is used.
LOG_ARCHIVE_DEST = path.
61. What is the use of ANALYZE command ?
To perform one of these function on an index, table, or cluster:
- to collect statistics about object used by the optimizer and store them in the data dictionary.
- to delete statistics about the object used by object from the data dictionary.
- to validate the structure of the object.
- to identify migrated and chained rows of the table or cluster.
MANAGING DISTRIBUTED DATABASES
62. How can we reduce the network traffic ?
- Replication of data in distributed environment.
- Using snapshots to replicate data.
- Using remote procedure calls.
63. What is snapshots ?
Snapshot is an object used to dynamically replicate data between distribute database at specified
time intervals. In ver 7.0 they are read only.
64. What are the various type of snapshots ?
Simple and Complex.
65. Differentiate simple and complex, snapshots ?
- A simple snapshot is based on a query that does not contains GROUP BY clauses, CONNECT BY clauses,
JOINs, sub-query or snapshot of operations.
- A complex snapshots contain at least any one of the above.
66. What dynamic data replication ?
Updating or Inserting records in remote database through database triggers. It may fail if remote
database is having any problem.
67. How can you Enforce Referential Integrity in snapshots ?
Time the references to occur when master tables are not in use.
Perform the reference the manually immediately locking the master tables. We can join tables in
snapshots by creating a complex snapshots that will based on the master tables.
68. What are the options available to refresh snapshots ?
COMPLETE – Tables are completely regenerated using the snapshot’s query and the master tables every
time the snapshot referenced.
FAST – If simple snapshot used then a snapshot log can be used to send the changes to the snapshot
tables.
FORCE – Default value. If possible it performs a FAST refresh; Otherwise it will perform a complete
refresh.
69. what is snapshot log ?
It is a table that maintains a record of modifications to the master table in a snapshot. It is
stored in the same database as master table and is only available for simple snapshots. It should be
created before creating snapshots.
70. When will the data in the snapshot log be used ?
We must be able to create a after row trigger on table (i.e., it should be not be already available
)
After giving table privileges.
We cannot specify snapshot log name because oracle uses the name of the master table in the name of
the database objects that support its snapshot log.
The master table name should be less than or equal to 23 characters.
(The table name created will be MLOGS_tablename, and trigger name will be TLOGS name).
72. What are the benefits of distributed options in databases ?
Database on other servers can be updated and those transactions can be grouped together with others
in a logical unit.
Database uses a two phase commit.
MANAGING BACKUP & RECOVERY
73. What are the different methods of backing up oracle database ?
- Logical Backups
- Cold Backups
- Hot Backups (Archive log)
74. What is a logical backup ?
Logical backup involves reading a set of database records and writing them into a file. Export
utility is used for taking backup and Import utility is used to recover from backup.
75. What is cold backup ? What are the elements of it ?
Cold backup is taking backup of all physical files after normal shutdown of database. We need to
take.
- All Data files.
- All Control files.
- All on-line redo log files.
- The init.ora file (Optional)
76. What are the different kind of export backups ?
Full back – Complete database
Incremental – Only affected tables from last incremental date/full backup date.
Cumulative backup – Only affected table from the last cumulative date/full backup date.
77. What is hot backup and how it can be taken ?
Taking backup of archive log files when database is open. For this the ARCHIVELOG mode should be
enabled. The following files need to be backed up.
All data files. All Archive log, redo log files. All control files.
78. What is the use of FILE option in EXP command ?
To give the export file name.
79. What is the use of COMPRESS option in EXP command ?
Flag to indicate whether export should compress fragmented segments into single extents.
80. What is the use of GRANT option in EXP command ?
A flag to indicate whether grants on database objects will be exported or not. Value is ‘Y’ or ‘N’.
81. What is the use of INDEXES option in EXP command ?
A flag to indicate whether indexes on tables will be exported.
82. What is the use of ROWS option in EXP command ?
Flag to indicate whether table rows should be exported. If ‘N’ only DDL statements for the database
objects will be created.
83. What is the use of CONSTRAINTS option in EXP command ?
A flag to indicate whether constraints on table need to be exported.
84. What is the use of FULL option in EXP command ?
A flag to indicate whether full database export should be performed.
85. What is the use of OWNER option in EXP command ?
List of table accounts should be exported.
86. What is the use of TABLES option in EXP command ?
List of tables should be exported.
87. What is the use of RECORD LENGTH option in EXP command ?
Record length in bytes.
88. What is the use of INCTYPE option in EXP command ?
Type export should be performed COMPLETE,CUMULATIVE,INCREMENTAL.
89. What is the use of RECORD option in EXP command ?
For Incremental exports, the flag indirects whether a record will be stores data dictionary tables
recording the export.
90. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
91. What is the use of PARFILE option in EXP command ?
Name of the parameter file to be passed for export.
92. What is the use of ANALYSE ( Ver 7) option in EXP command ?
A flag to indicate whether statistical information about the exported objects should be written to
export dump file.
93. What is the use of CONSISTENT (Ver 7) option in EXP command ?
A flag to indicate whether a read consistent version of all the exported objects should be
maintained.
94. What is use of LOG (Ver 7) option in EXP command ?
The name of the file which log of the export will be written.
95.What is the use of FILE option in IMP command ?
The name of the file from which import should be performed.
96. What is the use of SHOW option in IMP command ?
A flag to indicate whether file content should be displayed or not.
97. What is the use of IGNORE option in IMP command ?
A flag to indicate whether the import should ignore errors encounter when issuing CREATE commands.
98. What is the use of GRANT option in IMP command ?
A flag to indicate whether grants on database objects will be imported.
99. What is the use of INDEXES option in IMP command ?
A flag to indicate whether import should import index on tables or not.
100. What is the use of ROWS option in IMP command ?
A flag to indicate whether rows should be imported. If this is set to ‘N’ then only DDL for database
objects will be executed.
1. SNAPSHOT is used for
[DBA] a] Synonym, b] Table space, c] System server, d] Dynamic data
replication
Ans : D
2. We can create SNAPSHOTLOG for
[DBA] a] Simple snapshots, b] Complex snapshots, c] Both A & B, d]
Neither A nor B
Ans : A
3. Transactions per rollback segment is derived from
[DBA] a] Db_Block_Buffers, b] Processes, c] Shared_Pool_Size, d] None
of the above
Ans : B
4. ENQUEUE resources parameter information is derived from
[DBA] a] Processes or DDL_LOCKS and DML_LOCKS, b] LOG_BUFFER,
c] DB__BLOCK_SIZE..
Ans : A
5. LGWR process writes information into
a] Database files, b] Control files, c] Redolog files, d] All the
above.
Ans : C
6. SET TRANSACTION USE ROLLBACK SEGMENT is used to create user
objects
in a particular Tablespace
a] True, b] False
Ans : False
7. Databases overall structure is maintained in a file called
a] Redolog file, b] Data file, c] Control file, d] All of the
above.
Ans : C
8. These following parameters are optional in init.ora parameter file
DB_BLOCK_SIZE,
PROCESSES
a] True, b] False
Ans : False
9. Constraints cannot be exported through EXPORT command
a] True, b] False
Ans : False
10. It is very difficult to grant and manage common privileges needed by
different groups of
database users using the roles
a] True, b] False
Ans : False
11. What is difference between a DIALOG WINDOW and a DOCUMENT WINDOW
regarding
moving the window with respect to the application window
a] Both windows behave the same way as far as moving the window is
concerned.
b] A document window can be moved outside the application window while
a dialog
window cannot be moved
c] A dialog window can be moved outside the application window while a
document
window cannot be moved
Ans : C
12. What is the difference between a MESSAGEBOX and an ALERT
a] A messagebox can be used only by the system and cannot be used in
user application
while an alert can be used in user application also.
b] A alert can be used only by the system and cannot be use din user
application
while an messagebox can be used in user application also.
c] An alert requires an response from the userwhile a messagebox just
flashes a message
and only requires an acknowledment from the user
d] An message box requires an response from the userwhile a alert just
flashes a
message an only requires an acknowledment from the user
Ans : C
13. Which of the following is not an reason for the fact that most of the
processing is done at the
server ?
a] To reduce network traffic. b] For application sharing, c] To
implement business rules
centrally, d] None of the above
Ans : D
14. Can a DIALOG WINDOW have scroll bar attached to it ?
a] Yes, b] No
Ans : B
15. Which of the following is not an advantage of GUI systems ?
a] Intuitive and easy to use., b] GUI’s can display multiple
applications in multiple windows
c] GUI’s provide more user interface objects for a developer
d] None of the above
Ans
16. What is the difference between a LIST BOX and a COMBO BOX ?
a] In the list box, the user is restricted to selecting a value from a
list but in a combo box
the user can type in a value which is not in the list
b] A list box is a data entry area while a combo box can be used only
for control purposes
c] In a combo box, the user is restricted to selecting a value from a
list but in a list box the
user can type in a value which is not in the list
d] None of the above
Ans : A
17. In a CLIENT/SERVER environment , which of the following would not be
done at the client ?
a] User interface part, b] Data validation at entry line, c]
Responding to user events,
d] None of the above
Ans : D
18. Why is it better to use an INTEGRITY CONSTRAINT to validate data in a
table than to use a
STORED PROCEDURE ?
a] Because an integrity constraint is automatically checked while data
is inserted into or
updated in a table while a stored procedure has to be
specifically invoked
b] Because the stored procedure occupies more space in the database
than a integrity
constraint definition
c] Because a stored procedure creates more network traffic than a
integrity constraint
definition
Ans : A
19. Which of the following is not an advantage of a client/server model ?
a] A client/server model allows centralised control of data and
centralised implementation
of business rules.
b] A client/server model increases developer;s productivity
c] A client/server model is suitable for all applications
d] None of the above.
Ans : C
20. What does DLL stands for ?
a] Dynamic Language Library
b] Dynamic Link Library
c] Dynamic Load Library
d] None of the above
Ans : B
21. POST-BLOCK trigger is a
a] Navigational trigger
b] Key trigger
c] Transactional trigger
d] None of the above
Ans : A
22. The system variable that records the select statement that SQL * FORMS
most recently used
to populate a block is
a] SYSTEM.LAST_RECORD
b] SYSTEM.CURSOR_RECORD
c] SYSTEM.CURSOR_FIELD
d] SYSTEM.LAST_QUERY
Ans: D
23. Which of the following is TRUE for the ENFORCE KEY field
a] ENFORCE KEY field characterstic indicates the source of the value
that SQL*FORMS
uses to populate the field
b] A field with the ENFORCE KEY characterstic should have the INPUT
ALLOWED
charaterstic turned off
a] Only 1 is TRUE
b] Only 2 is TRUE
c] Both 1 and 2 are TRUE
d] Both 1 and 2 are FALSE
Ans : A
24. What is the maximum size of the page ?
a] Characters wide & 265 characters length
b] Characters wide & 265 characters length
c] Characters wide & 80 characters length
d] None of the above
Ans : B
25. A FORM is madeup of which of the following objects
a] block, fields only,
b] blocks, fields, pages only,
c] blocks, fields, pages, triggers and form level procedures,
d] Only blocks.
Ans : C
26. For the following statements which is true
1] Page is an object owned by a form
2] Pages are a collection of display information such as constant text
and graphics.
a] Only 1 is TRUE
b] Only 2 is TRUE
c] Both 1 & 2 are TRUE
d] Both are FALSE
Ans : B
27. The packaged procedure that makes data in form permanent in the
Database is
a] Post
b] Post form
c] Commit form
d] None of the above
Ans : C
28. Which of the following is TRUE for the SYSTEM VARIABLE $$date$$
a] Can be assigned to a global variable
b] Can be assigned to any field only during design time
c] Can be assigned to any variable or field during run time
d] None of the above
Ans : B
29. Which of the following packaged procedure is UNRESTRICTED ?
a] CALL_INPUT, b] CLEAR_BLOCK, c] EXECUTE_QUERY, d] USER_EXIT
Ans : D
30. Identify the RESTRICTED packaged procedure from the following
a] USER_EXIT, b] MESSAGE, c] BREAK, d] EXIT_FORM
Ans : D
31. What is SQL*FORMS
a] SQL*FORMS is a 4GL tool for developing & executing Oracle based
interactive
applications.
b] SQL*FORMS is a 3GL tool for connecting to the Database.
c] SQL*FORMS is a reporting tool
d] None of the above.
Ans : A
32. Name the two files that are created when you generate a form using
Forms 3.0
a] FMB & FMX, b] FMR & FDX, c] INP & FRM, d] None of the above
Ans : C
33. What is a trigger
a] A piece of logic written in PL/SQL
b] Executed at the arrival of a SQL*FORMS event
c] Both A & B
d] None of the above
Ans : C
34. Which of the folowing is TRUE for a ERASE packaged procedure
1] ERASE removes an indicated Global variable & releases the memory
associated with it
2] ERASE is used to remove a field from a page
1] Only 1 is TRUE
2] Only 2 is TRUE
3] Both 1 & 2 are TRUE
4] Both 1 & 2 are FALSE
Ans : 1
35. All datafiles related to a Tablespace are removed when the Tablespace
is dropped
a] TRUE
b] FALSE
Ans : B
36. Size of Tablespace can be increased by
a] Increasing the size of one of the Datafiles
b] Adding one or more Datafiles
c] Cannot be increased
d] None of the above
Ans : B
37. Multiple Tablespaces can share a single datafile
a] TRUE
b] FALSE
Ans : B
38. A set of Dictionary tables are created
a] Once for the Entire Database
b] Every time a user is created
c] Every time a Tablespace is created
d] None of the above
Ans : A
39. Datadictionary can span across multiple Tablespaces
a] TRUE
b] FALSE
Ans : B
40. What is a DATABLOCK
a] Set of Extents
b] Set of Segments
c] Smallest Database storage unit
d] None of the above
Ans : C
41. Can an Integrity Constraint be enforced on a table if some existing
table data does not satisfy
the constraint
a] Yes
b] No
Ans : B
42. A column defined as PRIMARY KEY can have NULL’s
a] TRUE
b] FALSE
Ans : B
43. A Transaction ends
a] Only when it is Committed
b] Only when it is Rolledback
c] When it is Committed or Rolledback
d] None of the above
Ans : C
44. A Database Procedure is stored in the Database
a] In compiled form
b] As source code
c] Both A & B
d] Not stored
Ans : C
45. A database trigger doesnot apply to data loaded before the definition
of the trigger
a] TRUE
b] FALSE
Ans : A
46. Dedicated server configuration is
a] One server process – Many user processes
b] Many server processes – One user process
c] One server process – One user process
d] Many server processes – Many user processes
Ans : C
47. Which of the following does not affect the size of the SGA
a] Database buffer
b] Redolog buffer
c] Stored procedure
d] Shared pool
Ans : C
48. What does a COMMIT statement do to a CURSOR
a] Open the Cursor
b] Fetch the Cursor
c] Close the Cursor
d] None of the above
Ans : D
49. Which of the following is TRUE
1] Host variables are declared anywhere in the program
2] Host variables are declared in the DECLARE section
a] Only 1 is TRUE
b] Only 2 is TRUE
c] Both 1 & 2are TRUE
d] Both are FALSE
Ans : B
50. Which of the following is NOT VALID is PL/SQL
a] Bool boolean;
b] NUM1, NUM2 number;
c] deptname dept.dname%type;
d] date1 date := sysdate
Ans : B.
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