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ORACLE Interview Questions and Answers

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(Continued from previous part...)

GENERAL INTERVIEW QUESTIONS (2)

16.What is the advantage of a stored procedure over a database trigger ?

We have control over the firing of a stored procedure but we have no control over the firing of a trigger.


17.What is the maximum no. of statements that can be specified in a trigger statement ?

One.


18.Can views be specified in a trigger statement ?

No


19.What are the values of :new and :old in Insert/Delete/Update Triggers ?

INSERT : new = new value, old = NULL
DELETE : new = NULL, old = old value
UPDATE : new = new value, old = old value


20.What are cascading triggers? What is the maximum no of cascading triggers at a time?

When a statement in a trigger body causes another trigger to be fired, the triggers are said to be cascading. Max = 32.


21.What are mutating triggers ?

A trigger giving a SELECT on the table on which the trigger is written.


22.What are constraining triggers ?

A trigger giving an Insert/Updat e on a table having referential integrity constraint on the triggering table.


23.Describe Oracle database's physical and logical structure ?

Physical : Data files, Redo Log files, Control file.
Logical : Tables, Views, Tablespaces, etc.


24.Can you increase the size of a tablespace ? How ?

Yes, by adding datafiles to it.


26.What is the use of Control files ?

Contains pointers to locations of various data files, redo log files, etc.


27.What is the use of Data Dictionary ?

Used by Oracle to store information about various physical and logical Oracle structures e.g. Tables, Tablespaces, datafiles, etc


28.What are the advantages of clusters ?

Access time reduced for joins.


29.What are the disadvantages of clusters ?

The time for Insert increases.


30.Can Long/Long RAW be clustered ?

No.

(Continued on next part...)

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ORACLE Interview Questions and Answers