Thursday, 12 April 2012

Oracle Interview Questions = Part -8

Where is the external query executed at the client or the server?
At the server.
Where is a procedure return in an external pl/sql library executed at the client or at the server?
At the client.
What is coordination Event?
Any event that makes a different record in the master block the current record is a coordination causing event.
What is the difference between OLE Server & Ole Container?
An Ole server application creates ole Objects that are embedded or linked in ole Containers ex. Ole servers are ms_word & ms_excel. OLE containers provide a place to store, display and manipulate objects that are created by ole server applications. Ex. oracle forms is an example of an ole Container.
What is an object group?
An object group is a container for a group of objects; you define an object group when you want to package related objects, so that you copy or reference them in other modules.
What is an LOV?
An LOV is a scrollable popup window that provides the operator with either a single or multi column selection list.
At what point of report execution is the before Report trigger fired?
After the query is executed but before the report is executed and the records are displayed.
What are the built -ins used for Modifying a groups structure?
ADD-GROUP_COLUMN (function)
ADD_GROUP_ROW (procedure)
DELETE_GROUP_ROW(procedure)
What is an user exit used for?
A way in which to pass control (and possibly arguments ) form Oracle report to another Oracle products of 3 GL and then return control ( and ) back to Oracle reports.
What is the User-Named Editor?
A user named editor has the same text editing functionality as the default editor, but, because it is a named object, you can specify editor attributes such as windows display size, position, and title.
My database was terminated while in BACKUP MODE, do I need to recover? (for DBA)
If a database was terminated while one of its tablespaces was in BACKUP MODE (ALTER TABLESPACE xyz BEGIN BACKUP;), it will tell you that media recovery is required when you try to restart the database. The DBA is then required to recover the database and apply all archived logs to the database. However, from Oracle7.2, you can simply take the individual datafiles out of backup mode and restart the database.
ALTER DATABASE DATAFILE '/path/filename' END BACKUP;
One can select from V$BACKUP to see which datafiles are in backup mode. This normally saves a significant amount of database down time.
Thiru Vadivelu contributed the following:
From Oracle9i onwards, the following command can be used to take all of the datafiles out of hot backup mode:
ALTER DATABASE END BACKUP;
The above commands need to be issued when the database is mounted.
What is a Static Record Group?
A static record group is not associated with a query, rather, you define its structure and row values at design time, and they remain fixed at runtime.
What is a record group?
A record group is an internal Oracle Forms that structure that has a column/row framework similar to a database table. However, unlike database tables, record groups are separate objects that belong to the form module which they are defined.
My database is down and I cannot restore. What now? (for DBA )
Recovery without any backup is normally not supported, however, Oracle Consulting can sometimes extract data from an offline database using a utility called DUL (Disk UnLoad). This utility reads data in the data files and unloads it into SQL*Loader or export dump files. DUL does not care about rollback segments, corrupted blocks, etc, and can thus not guarantee that the data is not logically corrupt. It is intended as an absolute last resort and will most likely cost your company a lot of money!!!
I've lost my REDOLOG files, how can I get my DB back? (for DBA)
The following INIT.ORA parameter may be required if your current redo logs are corrupted or blown away. Caution is advised when enabling this parameter as you might end-up losing your entire database. Please contact Oracle Support before using it. _allow_resetlogs_corruption = true
What is a property clause?
A property clause is a named object that contains a list of properties and their settings. Once you create a property clause you can base other object on it. An object based on a property can inherit the setting of any property in the clause that makes sense for that object.
What is a physical page ? & What is a logical page ?
A physical page is a size of a page. That is output by the printer. The logical page is the size of one page of the actual report as seen in the Previewer.
I've lost some Rollback Segments, how can I get my DB back? (for DBA)
Re-start your database with the following INIT.ORA parameter if one of your rollback segments is corrupted. You can then drop the corrupted rollback segments and create it from scratch.
Caution is advised when enabling this parameter, as uncommitted transactions will be marked as committed. One can very well end up with lost or inconsistent data!!! Please contact Oracle Support before using it. _Corrupted_rollback_segments = (rbs01, rbs01, rbs03, rbs04)
What are the differences between EBU and RMAN? (for DBA)
Enterprise Backup Utility (EBU) is a functionally rich, high performance interface for backing up Oracle7 databases. It is sometimes referred to as OEBU for Oracle Enterprise Backup Utility. The Oracle Recovery Manager (RMAN) utility that ships with Oracle8 and above is similar to Oracle7's EBU utility. However, there is no direct upgrade path from EBU to RMAN.
How does one create a RMAN recovery catalog? (for DBA)
Start by creating a database schema (usually called rman). Assign an appropriate tablespace to it and grant it the recovery_catalog_owner role. Look at this example:
sqlplus sys
SQL>create user rman identified by rman;
SQL> alter user rman default tablespace tools temporary tablespace temp;
SQL> alter user rman quota unlimited on tools;
SQL> grant connect, resource, recovery_catalog_owner to rman;
SQL> exit;
Next, log in to rman and create the catalog schema. Prior to Oracle 8i this was done by running the catrman.sql script. rman catalog rman/rman
RMAN>create catalog tablespace tools;
RMAN> exit;
You can now continue by registering your databases in the catalog. Look at this example:
rman catalog rman/rman target backdba/backdba
RMAN> register database;
How can a group in a cross products be visually distinguished from a group that does not form a cross product?
A group that forms part of a cross product will have a thicker border.
What is the frame & repeating frame?
A frame is a holder for a group of fields. A repeating frame is used to display a set of records when the no. of records that are to displayed is not known before.
What is a combo box?
A combo box style list item combines the features found in list and text item. Unlike the pop list or the text list style list items, the combo box style list item will both display fixed values and accept one operator entered value.
What are three panes that appear in the run time pl/sql interpreter?
1. Source pane.
2. interpreter pane.
3. Navigator pane.
What are the two panes that Appear in the design time pl/sql interpreter?
1. Source pane.
2. Interpreter pane
What are the two ways by which data can be generated for a parameters list of values?
1. Using static values.
2. Writing select statement.
What are the various methods of performing a calculation in a report ?
1. Perform the calculation in the SQL statements itself.
2. Use a calculated / summary column in the data model.
What are the default extensions of the files created by menu module?
.mmb,
.mmx
What are the default extensions of the files created by forms modules?
.fmb - form module binary
.fmx - form module executable
To display the page no. for each page on a report what would be the source & logical page no. or & of physical page no.?
& physical page no.

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