Important Oracle Database Development Interview Questions
Q – 1 Explain Dynamic Performance View in Oracle?
Ans- Oracle contains a set of underlying views that are maintained by the database server and accessible to the database administrator user SYS. These views are called dynamic performance views because they are continuously updated while a database is open and in use, and their contents relate primarily to performance. Although these views appear to be regular database tables, they are not.
These views provide data on internal disk structures and memory structures. You can select from these views, but you can never update or alter them.
Q – 2 Static Data Dictionary in Oracle?
Ans- Data dictionary tables are not directly accessible, but you can access information in them through data dictionary views. To list the data dictionary views available to you, query the view DICTIONARY. Many data dictionary tables have three corresponding views:
* An ALL_ view displays all the information accessible to the current user, including information from the current user’s schema as well as information from objects in other schemas, if the current user has access to those objects by way of grants of privileges or roles.
* A DBA_ view displays all relevant information in the entire database. DBA_ views are intended only for administrators. They can be accessed only by users with the SELECT ANY TABLE privilege. This privilege is assigned to the DBA role when the system is initially installed.
* A USER_ view displays all the information from the schema of the current user. No special privileges are required to query these views.
Q – 3 Explain Oracle Built-in Data Types?
Ans- There are 20 Oracle built-in data types, divided into 6 groups:
* Character Datatypes – CHAR, NCHAR, NVARCHAR2, VARCHAR2
* Number Datatypes – NUMBER, BINARY_FLOAT, BINARY_DOUBLE
* Long and Row Datatypes – LONG, LONG RAW, RAW
* Datetime Datatypes – DATE, TIMESTAMP, INTERVAL YEAR TO MONTH, INTERVAL DAY TO SECOND
* Large Object Datatypes – BLOB, CLOB, NCLOB, BFILE
* Row ID Datatypes – ROWID, UROWID
Q – 4 Explain Oracle Server Autotrace in Oracle?
Ans- Autotrace is Oracle server feature that generates two statement execution reports very useful for performance tuning:
* Statement execution path – Shows you the execution loop logic of a DML statement.
* Statement execution statistics – Shows you various execution statistics of a DML statement.
To turn on the autotrace feature, the Oracle server DBA need to:
* Create a special table called PLAN_TABLE.
* Create a special security role called PLUSTRACE.
* Grant PLUSTRACE role your user account
Q – 5 How many categories of Data Types in Oracle?
Ans- Oracles supports the following categories of data types:
* Oracle Built-in Datatypes.
* ANSI, DB2, and SQL/DS Datatypes.
* User-Defined Types.
* Oracle-Supplied Types.
Q – 6 How you save Query output to a Local File?
Ans- Normally, when you run a SELECT statement in SQL*Plus, the output will be displayed on your screen. If you want the output to be saved to local file, you can use the “SPOOL fileName” command to specify a local file and start the spooling feature.
When you are done with your SELECT statement, you need to close the spool file with the “SPOOL OFF” command. The following tutorial exercise gives you a good example:
SQL> connect HR/retneclgg
SQL> SET HEADING OFF
SQL> SET FEEDBACK OFF
SQL> SET LINESIZE 1000
SQL> SPOOL empemployees.lst
SQL> SELECT * FROM EMPLOYEES;
……
SQL> SPOOL OFF
You should get all records in employees.lst with fixed length fields.
Q – 7 How you change SQL*Plus System Settings?
Ans- SQL*Plus environment is controlled a big list of SQL*Plus system settings. You can change them by using the SET command as shown in the following list:
* SET AUTOCOMMIT OFF – Turns off the auto-commit feature.
* SET FEEDBACK OFF – Stops displaying the “27 rows selected.” message at the end of the query output.
* SET HEADING OFF – Stops displaying the header line of the query output.
* SET LINESIZE 256 – Sets the number of characters per line when displaying the query output.
* SET NEWPAGE 2 – Sets 2 blank lines to be displayed on each page of the query output.
* SET NEWPAGE NONE – Sets for no blank lines to be displayed on each page of the query output.
* SET NULL ‘null’ – Asks SQL*Plus to display ‘null’ for columns that have null values in the query output.
* SET PAGESIZE 60 – Sets the number of lines per page when displaying the query output.
* SET TIMING ON – Asks SQL*Plus to display the command execution timing data.
* SET WRAP OFF – Turns off the wrapping feature when displaying query output.
Q – 8 How you Run PL/SQL Statements in SQL*Plus?
Ans- If you want to run a single PL/SQL statement in SQL*Plus, you need to use the EXECUTE command as shown in the following tutorial example:
SQL> SET SERVEROUTPUT ON
SQL> EXECUTE DBMS_OUTPUT.PUT_LINE(‘Welcome to globalguideline!’)
Welcome to globalguideline!
PL/SQL procedure successfully completed.
Q – 9 How you run SQL Commands in SQL*Plus?
Ans- If you want to run a SQL command in SQL*Plus, you need to enter the SQL command in one or more lines and terminated with (;). The tutorial exercise below shows a good example:
SQL> SELECT ‘Welcome!’ FROM DUAL;
‘WELCOME
——–
Welcome!
SQL> SELECT ‘Welcome to globalguideline.com tutorials!’
2 FROM DUAL
3 ;
‘WELCOMETOglobalguideline.COMTUTORIALS!’
———————————–
Welcome to globalguideline.com tutorials!
Q – 10 Which types of Commands Can Be Executed in SQL*Plus?
Ans- There are 4 types of commands you can run at the SQL*Plus command line prompt:
1. SQL commands – Standard SQL statements to be executed on target database on the Oracle server. For example: “SELECT * FROM ggl_faq;” is a SQL command.
2. PL/SQL commands – PL/SQL statements to be executed by the Oracle server. For example: “EXECUTE DBMS_OUTPUT.PUT_LINE(‘Welcome to www.globalguideline.com’)” runs a PL/SQL command.
SQL*Plus commands – Commands to be executed by the local SQL*Plus program itself. For example: “SET NULL ‘NULL'” is a SQL*Plus command.
OS commands – Commands to be executed by the local operating system. For example: “HOST dir” runs an operating system command on the local machine.
Q – 11 What you do if DBA Lost the SYSTEM Password?
Ans- If the DBA lost the password of the SYSTEM user account, he/she can go to the Oracle server machine, and run SQL*Plus on server locally with the operating system authentication method to gain access to the database. The tutorial exercise below shows you how:
(Terminal server to the Oracle server machine)
(Start SQL*Plus)
SQL>CONNECT / AS SYSDBA
Connected.
SQL> ALTER USER SYSTEM IDENTIFIED BY ssap_lgg;
User altered.
Notice that the (/) in the CONNECT command tells SQL*Plus to use the current user on local operating system as the connection authentication method.
Q – 12 What Happens suppose if You Use a Wrong Connect Identifier?
Ans- Of course, you will get an error, if you use a wrong connect identifier. Here is an example of how SQL*Plus react to a wrong connect identifier:
SQL> CONNECT ggl/retneclgg@WRONG;
ERROR:
ORA-12154: TNS:could not resolve the connect identifier
specified
Warning: You are no longer connected to ORACLE.
What you need to do in this case:
* Check the CONNECT command to make sure that the connect identifier is entered correctly.
* Check the tnsnames.ora file to make sure that the connect identifier is defined correctly.
* Check the tnsnames.ora file to make sure that there is no multiple definitions of the same connect identifier.
* Check your files system to see if you have multiple copies of tnsnames.ora in different Oracle home directories, because you installed multiple versions of Oracle. If you do have multiple copies, make sure your SQL*Plus session is picking up the correct copy of tnsnames.ora.
Q – 13 How you Connect a SQL*Plus Session to an Oracle Server?
Ans- In order to connect a SQL*Plus session to an Oracle server, you need to:
1. Obtain the connection information from the Oracle server DBA.
2. Define a new “connect identifier” called “ggl_XE” in your tnsnames.org file with the given connection information.
3. Run the CONNECT command in SQL*Plus as shown in the tutorial exercise below:
>cd c:oraclexeapporacleproduct10.2.0server
>.insqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 – Production on Tue …
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL> CONNECT ggl/retneclgg@ggl_XE;
Connected.
SQL> SELECT SYSDATE FROM DUAL;
SYSDATE
———
05-MAR-06
Q – 14 Explain Connect Identifier?
Ans- A “connect identifier” is an identification string of a single set of connection information to a specific target database instance on a specific Oracle server.
Connect identifiers are defined and stored in a file called tnsnames.ora located in $ORACLE_HOME/network/admin/ directory. Here is one example of a “connect identifier” definition:
ggl_XE =
(DESCRIPTION =
(ADDRESS =
(PROTOCOL = TCP)
(HOST = www.globalguideline.com)
(PORT = 1521)
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = XE)
)
)
The above “connect identifier” defines “TNS_XE” with the following connection information:
* The network hostname: www.globalguideline.com.
* The network port number: 1521.
* The name of the target database instance: XE.
Q – 15 What Information Is Needed to Connect SQL*Plus an Oracle Server?
Ans- If you want to connect your SQL*Plus session to an Oracle server, you need to know the following information about this server:
* The network hostname, or IP address, of the Oracle server.
* The network port number where the Oracle server is listening for incoming connections.
* The name of the target database instance managed by the Oracle server.
* The name of your user account predefined on in the target database instance.
* The password of your user account predefined on in the target database instance.
Q – 16 How you Start the Command-Line SQL*Plus?
Ans- f you Oracle server or client installed on your windows system, you can start the command-line SQL*Plus in two ways:
1. Click Start > All Programs > Oracle … > Start SQL Command Line. The SQL*Plus command window will show up with a message like this:
SQL*Plus: Release 10.2.0.1.0 – Production on Tue …
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL>
2. Click Start > Run…, enter “cmd” and click OK. A Windows command window will show up. You can then use Windows commands to start the command-line SQL*Plus as shown in the tutorial exercise below:
>cd c:oraclexeapporacleproduct10.2.0server
>.insqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 – Production on Tue …
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Q – 17 How you Check the Server Version in Oracle?
Ans- Oracle server version information is stored in a table called: PRODUCT_COMPONENT_VERSION. You can use a simple SELECT statement to view the version information like this:
>.insqlplus
Enter user-name: SYSTEM/globalguideline AS SYSDBA
Connected to an idle instance
SQL> COL PRODUCT FORMAT A35
SQL> COL VERSION FORMAT A15
SQL> COL STATUS FORMAT A15
SQL> SELECT * FROM PRODUCT_COMPONENT_VERSION;
PRODUCT VERSION STATUS
———————————– ———– ———-
NLSRTL 10.2.0.1.0 Production
Oracle Database 10g Express Edition 10.2.0.1.0 Product
PL/SQL 10.2.0.1.0 Production
TNS for 32-bit Windows: 10.2.0.1.0 Production
Q – 18 What you do if the Binary SPFile is wrong for the Default Instance?
Ans- Let’s say the SPFile for the default instance is a binary file, and some settings are wrong in the SPFile, like SGA setting is bellow 20MB, how do you change a setting in the binary file? This seems to be a hard task, because the binary SPFile is not allowed to be edited manually. It needs to be updated by the server with instance started. But you can not start the instance because the SPFile has a wrong setting.
One way to solve the problem is to stop using the binary SPFile, and use a text version of the a parameter file to start the instance. Here is an example of how to use the backup copy (text version) of the parameter file for the default instance to start the instance:
.insqlplus
Enter user-name: SYSTEM/globalguideline AS SYSDBA
Connected to an idle instance
Q – 19 Where are settings stored for Each Instance in Oracle?
Ans- Settings for each instance are stored in a file called Server Parameter File (SPFile). Oracle supports two types of parameter files, Text type, and Binary type. parameter files should be located in $ORACLE_HOMEdatabase directory. A parameter file should be named like “init$SID.ora”, where $SID is the instance name.
Q – 20 How do you use “startup” Command to Start Default Instance?
Ans- If you logged in to the server as a SYSDBA, you start the default instance with the “startup” command. Here is how to start the default instance in SQL*Plus in SYSDBA mode:
>.insqlplus
Enter user-name: SYSTEM/globalguideline AS SYSDBA
Connected to an idle instance
SQL> show instance
instance “local”
SQL> startup
ORA-00821: Specified value of sga_target 16M is too small,
needs to be at least 20M
Now the server is telling you more details about the memory problem on your default instance: your SGA setting of 16MB is too small. It must be increased to at least 20MB.
Q – 21 How you Login to the Server without an Instance?
Ans- If your default instance is in trouble, and you can not use the normal login process to reach the server, you can use a special login to log into the server without any instance. Here is how to use SQL*Plus to log in as as a system BDA:
>cd (OracleXE home directory)
>.instartdb
>.insqlplus
Enter user-name: SYSTEM/globalguideline AS SYSDBA
Connected to an idle instance
SQL> show instance
instance “local”
The trick is to put user name, password and login options in a single string as the user name. “AS SYSDBA” tells the server to not start any instance, and connect the session the idle instance.
Log in as SYSDBA is very useful for performing DBA tasks.
Q – 22 What to do if StartBD.bat failed to start the XE Instance?
Ans- If StartBD.bat failed to start the XE instance, you need to try to start the instance with other approaches to get detail error messages on why the instance can not be started.
One good approach to start the default instance is to use SQL*Plus. Here is how to use SQL*Plus to start the default instance in a command window:
>cd (OracleXE home directory)
>.instartdb
>.insqlplus
Enter user-name: SYSTEM
Enter password: globalguideline
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
The first “cd” is to move the current directory the 10g XE home directory. The second command “.instartdb” is to make sure the TNS listener is running. The third command “.insqlplus” launches SQL*Plus. The error message “ORA-27101” tells you that there is a memory problem with the default instance.
So you can not use the normal login process to the server without a good instance. See other tips on how to log into a server without any instance.
Q – 23 What happened if you Set the SGA Too Low in Oracle?
Ans- Let’s you made a mistake and changed to SGA to 16MB from the SYSTEM admin home page. When you run the batch file StartDB.bat, it will return a message saying server stated. However, if you try to connect to your server home page: http://localhost:8080/apex/, you will get no response. Why? Your server is running, but the default instance XE was not started.
If you go the Control Panel and Services, you will see service OracleServiceXE is listed not in the running status.
Q – 24 How you change program Global Area (PGA) in Oracle?
Ans- Your 10g XE server has a default setting for Program Global Area (PGA) of 40MB. The PGA size can be changed to a new value depending on how much data a single session should be allocated. If you think your session will be short with a small amount of data, you should change the PGA size to 16MB by:
* Log into the server home page as SYSTEM.
* Go to Administration, then Memory.
* Click Configure PGA.
* Enter the new memory size: 16
* Click Apply Changes to save the changes.
* Re-start your server.
Q – 25 How you can Change System Global Area (SGA) in Oracle?
Ans- Your 10g XE server has a default setting for System Global Area (SGA) of 140MB. The SGA size can be changed to a new value depending on how many concurrent sessions connecting to your server. If you are running this server just for yourself to improve your DBA skill, you should change the SGA size to 32MB by:
* Log into the server home page as SYSTEM.
* Go to Administration, then Memory.
* Click Configure SGA.
* Enter the new memory size: 32
* Click Apply Changes to save the changes.
* Re-start your server.
Q – 26 How you Unlock the Sample User Account in Oracle?
Ans- Your 10g XE server comes with a sample database user account called HR. But this account is locked. You must unlock it before you can use it:
* Log into the server home page as SYSTEM.
* Click the Administration icon, and then click Database Users.
* Click the HR schema icon to display the user information for HR.
* Enter a new password (hr) for HR, and change the status to Unlocked.
* Click Alter User to save the changes.
Now user account HR is ready to use.
Q – 27 How you Shutdown your 10g XE Server from Command Line?
Ans- You can shutdown your 10g XE server from command line by:
* Open a command line window.
* Change directory to oraclexeapporacleproduct10.2.0serverBIN.
* Run StopDB.bat.
The batch file StopDB.bat contains:
net stop OracleServiceXE
Q – 28 How you start your 10g XE Server from Command Line?
Ans- You can start your 10g XE server from command line by:
* Open a command line window.
* Change directory to oraclexeapporacleproduct10.2.0serverBIN.
* Run StartDB.bat.
The batch file StartDB.bat contains:
net start OracleXETNSListener
net start OracleServiceXE
@oradim -startup -sid XE -starttype inst > nul 2>&1
Q – 29 Tell me how much memory your 10g XE Server is using?
Ans- Your 10g XE Server is using about 180MB of memory even there is no users on the server. The server memory usage is displayed on your server home page, if you log in as SYSTEM.
Q – 30 How you start your 10g XE Server?
Ans- Go to the Start menu, select All Programs, Oracle Database 10g Express Edition, and Start Database.
Q – 31 How you Shutdown Your 10g XE Server?
Ans- If you want to shutdown your 10g Express Edition server, go to the Services manager in the control panel. You will a service called OracleServiceXE, which represents your 10g Express Edition server.
Select OracleServiceXE, and use the right mouse click to stop this service. This will shutdown your 10g Express Edition server.
You can also shutdown your 10g XE server through the start menu. Select All Programs, then Oracle Database 10g Express Edition, and then Stop Database.
Q – 32 How you can Check your Oracle Database 10g XE Installation?
Ans- If you want to check your fresh installation of 10g Express Edition without using any special client programs, you can use a Web browser with this address, http://localhost:8080/apex/.
You will see the login page. Enter SYSTEM as the user name, and the password (globalguideline), you selected during the installation to log into the server.
Visit different areas on your 10g XE server home page to make sure your server is running OK.
You can also get to your 10g XE server home page by going through the start menu. Select All Programs, then Oracle Database 10g Express Edition, and then Go To Database Home Page.
Q – 33 Explain Install Oracle Database 10g XE?
Ans- To install 10g universal edition, double click, OracleXEUniv.exe, the install wizard starts. It will guide you to finish the installation process. You should take notes about:
* The SYSTEM password you selecte: globalguideline.
* Database server port: 1521.
* Database HTTP port: 8080.
* MS Transaction Server port: 2030.
* The directory where 10g XE is installed: oraclexe
* Hard disk space taken: 1655MB.
Q – 34 How you can Download Oracle Database 10g XE?
Ans- If you want to download a copy of Oracle Database 10g Express Edition, visit http://www.oracle.com/technology/software/products/database/xe/.
If you are using Windows systems, there are downloads available for you:
* Oracle Database 10g Express Edition (Western European) – Single-byte LATIN1 database for Western European language storage, with the Database Homepage user interface in English only.
* Oracle Database 10g Express Edition (Universal) – Multi-byte Unicode database for all language deployment, with the Database Homepage user interface available in the following languages: Brazilian Portuguese, Chinese (Simplified and Traditional), English, French, German, Italian, Japanese, Korean and Spanish.
* Oracle Database 10g Express Client
You need to download the universal edition, OracleXEUniv.exe, (216,933,372 bytes) and client package, OracleXEClient.exe (30,943,220 bytes).
Q – 35 Which Operating Systems Are Supported by Oracle Database 10g XE?
Ans- Oracle Database 10g Express Edition is available for two types of operating Systems:
* Linux x86 – Debian, Mandriva, Novell, Red Hat and Ubuntu
* Microsoft Windows
Q – 36 Described the limitations of Oracle Database 10g XE?
Ans- Oracle Database XE is free for runtime usage with the following limitations:
* Supports up to 4GB of user data (in addition to Oracle system data)
* Single instance only of Oracle Database XE on any server
* May be installed on a multiple CPU server, but only executes on one processor in any server
* May be installed on a server with any amount of memory, but will only use up to 1GB RAM of available memory
Q – 37 Explain Oracle Database 10g Express Edition?
Ans- Based on Oracle Web site: Oracle Database 10g Express Edition (Oracle Database XE) is an entry-level, small-footprint database based on the Oracle Database 10g Release 2 code base that’s free to develop, deploy, and distribute; fast to download; and simple to administer. Oracle Database XE is a great starter database for:
* Developers working on PHP, Java, .NET, and Open Source applications
* DBAs who need a free, starter database for training and deployment
* Independent Software Vendors (ISVs) and hardware vendors who want a starter database to distribute free of charge
* Educational institutions and students who need a free database for their curriculum
Q – 38 Explain Open Database Communication (ODBC) in Oracle?
Ans- ODBC, Open Database Communication, a standard API (application program interface) developed by Microsoft for Windows applications to communicate with database management systems.
Oracle offers ODBC drivers to allow Windows applications to connect Oracle server through ODBC.
Q – 39 Explain Transport Network Substrate (TNS) in Oracle?
Ans- TNS, Transport Network Substrate, is a foundation technology, built into the Oracle Net foundation layer that works with any standard network transport protocol.
Q – 40 Explain SQL Plus?
Ans- SQL Plus is an interactive and batch query tool that is installed with every Oracle Database Server or Client installation. It has a command-line user interface, a Windows Graphical User Interface (GUI) and the iSQL*Plus web-based user interface.
Q – 41 Explain Recycle Bin in Oracle?
Ans- Recycle bin is a logical storage to hold the tables that have been dropped from the database, in case it was dropped in error. Tables in recycle bin can be recovered back into database by the Flashback Drop action. Oracle database recycle save the same purpose as the recycle bin on your Windows desktop.
Recycle bin can be turned on or off in the recyclebin=on/off in your parameter file.
Q – 42 Explain User Role in Oracle?
Ans- A user role is a group of privileges. Privileges are assigned to users through user roles. You create new roles, grant privileges to the roles, and then grant roles to users.
Q – 43 Explain Oracle Database?
Ans- An Oracle database is a collection of data treated as a big unit in the database server.
Q – 44 Explain Oracle Tablespace?
Ans- An Oracle tablespace is a big unit of logical storage in an Oracle database. It is managed and used by the Oracle server to store structures data objects, like tables and indexes.
Q – 45 Explain Oracle Data File?
Ans- An Oracle data file is a big unit of physical storage in the OS file system. One or many Oracle data files are organized together to provide physical storage to a single Oracle tablespace.
Q – 46 Explain Table Index in Oracle?
Ans- Index is an optional structure associated with a table that allow SQL statements to execute more quickly against a table. Just as the index in this manual helps you locate information faster than if there were no index, an Oracle Database index provides a faster access path to table data. You can use indexes without rewriting any queries. Your results are the same, but you see them more quickly.
Q – 47 Explain Database Table in Oracle?
Ans- A database table is a basic unit of data logical storage in an Oracle database. Data is stored in rows and columns. You define a table with a table name, such as employees, and a set of columns. You give each column a column name, such as employee_id, last_name, and job_id; a datatype, such as VARCHAR2, DATE, or NUMBER; and a width.
The width can be predetermined by the datatype, as in DATE. If columns are of the NUMBER datatype, define precision and scale instead of width. A row is a collection of column information corresponding to a single record.
Q – 48 Explain Database Schema in Oracle?
Ans- A schema is a collection of logical structures of data, or schema objects. A schema is owned by a database user and has the same name as that user. Each user owns a single schema. Schema objects can be created and manipulated with SQL and include: tables, views, and other types of data objects.
Q – 49 Described the Relation of a User Account and a Schema in Oracle?
Ans- User accounts and schemas have a one-to-one relation. When you create a user, you are also implicitly creating a schema for that user. A schema is a logical container for the database objects (such as tables, views, triggers, and so on) that the user creates. The schema name is the same as the user name, and can be used to unambiguously refer to objects owned by the user.
Q – 50 Explain User Account in Oracle?
Ans- A user account is identified by a user name and defines the user’s attributes, including the following:
* Password for database authentication
* Privileges and roles
* Default tablespace for database objects
* Default temporary tablespace for query processing work space
Q – 51 Explain Program Global Area (PGA) in Oracle?
Ans- A Program Global Area (PGA) is a memory buffer that is allocated for each individual database session and it contains session specific information such as SQL statement data or buffers used for sorting. The value specifies the total memory allocated by all sessions, and changes will take effect as new sessions are started.
Q – 52 Explain System Global Area (SGA) in Oracle?
Ans- The System Global Area (SGA) is a memory area that contains data shared between all database users such as buffer cache and a shared pool of SQL statements. The SGA is allocated in memory when an Oracle database instance is started, and any change in the value will take effect at the next startup.
Q – 53 Explain Initialization Parameter File in Oracle?
Ans- An initialization parameter file is a text file that contains a list of initialization parameters. The file should be written in the client’s default character set. Sample initialization parameter files are provided on the Oracle distribution medium for each operating system.
A sample file is sufficient for initial use, but you will probably want to modify the file to tune the database for best performance. Any changes will take effect after you completely shut down and restart the instance.
Q – 54 Explain Server Parameter File in Oracle?
Ans- A server parameter file is a binary file that acts as a repository for initialization parameters. The server parameter file can reside on the machine where the Oracle database server executes. Initialization parameters stored in a server parameter file are persistent, in that any changes made to the parameters while an instance is running can persist across instance shutdown and startup.
Q – 55 Explain Parameter File in Oracle?
Ans- A parameter file is a file that contains a list of initialization parameters and a value for each parameter. You specify initialization parameters in a parameter file that reflect your particular installation. Oracle supports the following two types of parameter files:
* Server Parameter Files – Binary version. Persistent.
* Initialization Parameter Files – Text version. Not persistent.
Q – 56 Explain Oracle Instance?
Ans- Every running Oracle database is associated with an Oracle instance. When a database is started on a database server (regardless of the type of computer), Oracle allocates a memory area called the System Global Area (SGA) and starts one or more Oracle processes. This combination of the SGA and the Oracle processes is called an Oracle instance.
The memory and processes of an instance manage the associated database’s data efficiently and serve the one or multiple users of the database.
Q – 57 Explain Oracle?
Ans- Oracle is a company. Oracle is also a database server, which manages data in a very structured way. It allows users to store and retrieve related data in a multiuser environment so that many users can concurrently access the same data. All this is accomplished while delivering high performance. A database server also prevents unauthorized access and provides efficient solutions for failure recovery.