Oracle FAQs Questions with Answers # 8

What is the purpose of the product order option in the column property sheet?

To specify the order of individual group evaluation in a cross products.

What is the use of image_zoom built-in?

To manipulate images in image items.

How do you reference a parameter indirectly?

To indirectly reference a parameter use the NAME IN, COPY 'built-ins to indirectly set and reference the parameters value' Example name_in ('capital parameter my param'), Copy ('SURESH','Parameter my_param')

What is a timer?
Timer is an "internal time clock" that you can programmatically create to perform an action each time the times.

What are the two phases of block coordination?

There are two phases of block coordination: the clear phase and the population phase. During, the clear phase, Oracle Forms navigates internally to the detail block and flushes the obsolete detail records. During the population phase, Oracle Forms issues a SELECT statement to repopulate the detail block with detail records associated with the new master record. These operations are accomplished through the execution of triggers.

What are Most Common types of Complex master-detail relationships?

There are three most common types of complex master-detail relationships:

  • master with dependent details
  • master with independent details
  • detail with two masters
What is a text list?

The text list style list item appears as a rectangular box which displays the fixed number of values. When the text list contains values that can not be displayed, a vertical scroll bar appears, allowing the operator to view and select undisplayed values.

What is term?

The term is terminal definition file that describes the terminal form which you are using r20run.

What is use of term?

The term file which key is correspond to which oracle report functions.

What is pop list?

The pop list style list item appears initially as a single field (similar to a text item field). When the operator selects the list icon, a list of available choices appears.

What is the maximum no of chars the parameter can store?

The maximum no of chars the parameter can store is only valid for char parameters, which can be upto 64K. No parameters default to 23Bytes and Date parameter default to 7Bytes.

What are the default extensions of the files created by library module?

The default file extensions indicate the library module type and storage format .pll - pl/sql library module binary

What are the Coordination Properties in a Master-Detail relationship?

The coordination properties are

  • Deferred
  • Auto-Query
These Properties determine when the population phase of block
coordination should occur.

How do you display console on a window?

The console includes the status line and message line, and is displayed at the bottom of the window to which it is assigned.To specify that the console should be displayed, set the console window form property to the name of any window in the form. To include the console, set console window to Null.

What are the different Parameter types?

Text ParametersData Parameters

State any three mouse events system variables?

System.mouse_button_pressedSystem.mouse_button_shift

What are the types of calculated columns available?

Summary, Formula, Placeholder column.

Explain about stacked canvas views?

Stacked canvas view is displayed in a window on top of, or "stacked" on the content canvas view assigned to that same window. Stacked canvas views obscure some part of the underlying content canvas view, and or often shown and hidden programmatically.

How does one do off-line database backups? (for DBA)

Shut down the database from sqlplus or server manager. Backup all files to secondary storage (eg. tapes). Ensure that you backup all data files, all control files and all log files. When completed, restart your database.

Do the following queries to get a list of all files that needs to be backed up:

  • select name from sys.v_$datafile;
  • select member from sys.v_$logfile;
  • select name from sys.v_$controlfile;
Sometimes Oracle takes forever to shutdown with the "immediate" option. As workaround to this problem, shutdown using these commands:
  • alter system checkpoint;
  • shutdown abort
  • startup restrict
  • shutdown immediate
Note that if you database is in ARCHIVELOG mode, one can still use archived log files to roll forward from an off-line backup. If you cannot take your database down for a cold (off-line) backup at a convenient time, switch your database into ARCHIVELOG mode and perform hot (on-line) backups.

What is the difference between SHOW_EDITOR and EDIT_TEXTITEM?

Show editor is the generic built-in which accepts any editor name and takes some input string and returns modified output string. Whereas the edit_textitem built-in needs the input focus to be in the text item before the built-in is executed.

What are the built-ins that are used to Attach an LOV programmatically to an item?

  • set_item_property
  • get_item_property
  • (by setting the LOV_NAME property)
How does one do on-line database backups? (for DBA)

Each tablespace that needs to be backed-up must be switched into backup mode before copying the files out to secondary storage (tapes). Look at this simple example.

ALTER TABLESPACE xyz BEGIN BACKUP;
! cp xyfFile1 /backupDir/

ALTER TABLESPACE xyz END BACKUP;

It is better to backup tablespace for tablespace than to put all tablespaces in backup mode. Backing them up separately incurs less overhead. When done, remember to backup your control files. Look at this example:

ALTER SYSTEM SWITCH LOGFILE; -- Force log switch to update control file headers
ALTER DATABASE BACKUP CONTROLFILE TO '/backupDir/control.dbf';

NOTE: Do not run on-line backups during peak processing periods. Oracle will write complete database blocks instead of the normal deltas to redo log files while in backup mode. This will lead to excessive database archiving and even database freezes.

How does one backup a database using RMAN? (for DBA)

The biggest advantage of RMAN is that it only backup used space in the database. Rman doesn't put tablespaces in backup mode, saving on redo generation overhead. RMAN will re-read database blocks until it gets a consistent image of it. Look at this simple backup example.

rman target sys/*** nocatalog
run {
allocate channel t1 type disk;
backup
format '/app/oracle/db_backup/%d_t%t_s%s_p%p'
( database );
release channel t1;
}
Example RMAN restore:
rman target sys/*** nocatalog
run {
allocate channel t1 type disk;
# set until time 'Aug 07 2000 :51';
restore tablespace users;
recover tablespace users;
release channel t1;
}

The examples above are extremely simplistic and only useful for illustrating basic concepts. By default Oracle uses the database controlfiles to store information about backups. Normally one would rather setup a RMAN catalog database to store RMAN metadata in. Read the Oracle Backup and Recovery Guide before implementing any RMAN backups.

Note: RMAN cannot write image copies directly to tape. One needs to use a third-party media manager that integrates with RMAN to backup directly to tape. Alternatively one can backup to disk and then manually copy the backups to tape.

What are the different file extensions that are created by oracle reports?

Rep file and Rdf file.

What is strip sources generate options?

Removes the source code from the library file and generates a library files that contains only pcode. The resulting file can be used for final deployment, but can not be subsequently edited in the designer.ex. f45gen module=old_lib.pll userid=scott/tiger strip_source YES output_file

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