Tuesday, 5 November 2013

Oracle Interview Questions 15



Can functions be overloaded ?
Answer: Yes.
Can 2 functions have same name & input parameters but differ only by return datatype
Answer: No.
What are the constructs of a procedure, function or a package ?
Answer: The constructs of a procedure, function or a package are :
variables and constants
cursors
exceptions
Why Create or Replace and not Drop and recreate procedures ?
Answer: So that Grants are not dropped.
Can you pass parameters in packages ? How ?
Answer: Yes.You can pass parameters to procedures or functions in a package.
What are the parts of a database trigger ?
Answer: The parts of a trigger are:
A triggering event or statement
A trigger restriction
A trigger action
What are the various types of database triggers ?
Answer: There are 12 types of triggers, they are combination of :
Insert, Delete and Update Triggers.
Before and After Triggers.
Row and Statement Triggers.
What is the advantage of a stored procedure over a database trigger ?
Answer: We have control over the firing of a stored procedure but we have no control over the firing of
a trigger.
What is the maximum no.of statements that can be specified in a trigger statement ?
Answer: One.
Can views be specified in a trigger statement ?
Answer: No
What are the values of :new and :old in Insert/Delete/Update Triggers ?
Answer: INSERT : new = new value, old = NULL
DELETE : new = NULL, old = old value
UPDATE : new = new value, old = old value
What are cascading triggers? What is the maximum no of cascading triggers at a time?
Answer: When a statement in a trigger body causes another trigger to be fired, the triggers are said to
be cascading.Max = 32.
What are mutating triggers ?
Answer: A trigger giving a SELECT on the table on which the trigger is written.
What are constraining triggers ?
Answer: A trigger giving an Insert/Updat e on a table having referential integrity constraint on the
triggering table.
Describe Oracle database's physical and logical structure ?
Answer: Physical : Data files, Redo Log files, Control file.
Logical : Tables, Views, Tablespaces, etc.
Can you increase the size of a tablespace ? How ?
Answer: Yes, by adding datafiles to it.
Can you increase the size of datafiles ? How ?
Answer: No (for Oracle 7.0)
Yes (for Oracle 7.3 by using the Resize clause )
What is the use of Control files ?
Answer: Contains pointers to locations of various data files, redo log files, etc.
What is the use of Data Dictionary ?
Answer: It Used by Oracle to store information about various physical and logical Oracle structures
e.g.Tables, Tablespaces, datafiles, etc
What are the advantages of clusters ?
Answer: Access time reduced for joins.
What are the disadvantages of clusters ?
Answer: The time for Insert increases.
Can Long/Long RAW be clustered ?
Answer: No.
Can null keys be entered in cluster index, normal index ?
Answer: Yes.
Can Check constraint be used for self referential integrity ? How ?
Answer: Yes.In the CHECK condition for a column of a table, we can reference some other column of
the same table and thus enforce self referential integrity.
What are the min.extents allocated to a rollback extent ?
Answer: Two
What are the states of a rollback segment ? What is the difference between partly
available and needs recovery ?
Answer: The various states of a rollback segment are :
ONLINE
OFFLINE
PARTLY AVAILABLE
NEEDS RECOVERY

INVALID. 

No comments:

Post a Comment