Oracle Questions

We can apply at max of 12 triggers in a table.

Named PL/SQL blocks of code which can be invoked using parameters are called PL/SQL sub programs.

Advantages of PL/SQL subprograms are

- The application makes a single call to the database to run a block of statements which improves performance against running SQL multiple times. This will reduce the number of calls between the database and the application.

- PL/SQL is secure since the code resides inside the database thus hiding internal database details from the application. The application will only make a call to the PL/SQL sub program

- PL/SQL and SQL go hand in hand so there would be no need of any translation required between PL/SQL and SQL.

When any file is attempted to edit without any arguments (example ed or edit), the last SQL command is saved in AFIEDT.BUF, It acts like a default buffer file for edit commands.

Row Level Trigger :
Row Level Trigger is fired each time row is affected by Insert, Update or Delete command. If statement doesn’t affect any row, no trigger action happens.

Statement Level Trigger :
This kind of trigger fires when a SQL statement affects the rows of the table. The trigger activates and performs its activity irrespective of number of rows affected due to SQL statement.

Oracle HTTP Server is the Web server component of Oracle Database. It is based on the Apache HTTP Server. It is robust and reliable server due to following features:

- Provide high availability infrastructure integration with Oracle Process Manager and Notification Server (OPMN), for process management, death detection and failover for Oracle HTTP Server processes.

- Provide Dynamic Monitoring Services (DMS) metrics that give runtime performance statistics for Oracle HTTP Server processes.

- Enable securing of transactions with Secure Sockets Layer (SSL) technology.

- Execute Perl scripts in the same process as the Oracle HTTP Server, or as CGI script.

ANALYZE command is used to perform various functions on index, table, or cluster, as listed below:
- It helps in dentifying migrated and chained rows of the table or cluster.
- It helps in validating the structure of the object.
- It helps in collecting the statistics about object used by the optimizer. They are then stored in the data dictionary.
- It helps in deleting statistics used by object from the data dictionary.

- Online backup is one which is taken at the time the database is running in the ARCHIVELOG mode.

- Following files should be backed up during the Offline Backup: All data file, all control file and all online redo log file. But in the case of the online backup following files is backed up: All data files all archived redo log files and one control file via the alter database command.

- Offline database we cannot rely upon but in case of online database no issues.

- Offline backup no archived mode is required but in the online backup it is must.

Insert image into a table

Create the following table:

      create table pics_table (

      bfile_id number,

      bfile_desc varchar2(30),

      bfile_loc bfile,

      bfile_type varchar2(4))

      TABLESPACE appl_data

      storage (initial 1m next 1m pctincrease 0) 

Insert Query:

      INSERT INTO pics_table

      VALUES(4,'test image',bfilename('GIF_FILES','Test.JPG'),'JPEG');