| forced view [message #122543] |
Tue, 07 June 2005 03:49  |
ramvenky
Messages: 5
Registered: May 2005
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Junior Member |
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I had an interview last week.The Interviewer asked what is forced view.but I don't know what it is?.Please tell about forced view
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| Re: forced view [message #122546 is a reply to message #122543] |
Tue, 07 June 2005 03:59  |
girish.rohini
Messages: 744
Registered: April 2005
Location: Delhi (India)
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Senior Member |
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Force is a keyword. It Forces The Creation Of A View Even When The View Will Be Invalid. NoForce Is The Default
eg: -- assuming the table xyz does not exist
CREATE FORCE VIEW view_force AS
SELECT * FROM xyz;
Its a feature in 10g
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| Re: forced view [message #122632 is a reply to message #122543] |
Tue, 07 June 2005 12:24 |
smartin
Messages: 1803
Registered: March 2005
Location: Jacksonville, Florida
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Senior Member |
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It has always seemed a tad strange to me that you have to force the creation of a view, if that view will be invalid, yet you don't have to force the creation of a procedure.
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| Re: forced view [message #122684 is a reply to message #122543] |
Wed, 08 June 2005 00:20 |
nabeelkhan
Messages: 73
Registered: May 2005
Location: Kuwait
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Member |
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Work's in 9iR2 and 10gR1
use FORCE if you want to create the view regardless of whether the view's base tables or the referenced object types exist or the owner of the schema containing the view has privileges on them.
These conditions must be true before any SELECT, INSERT, UPDATE, or DELETE statements can be issued against the view
If the view definition contains any constraints, CREATE VIEW ... FORCE will fail if the base table does not exist or the referenced object type does not exist. CREATE VIEW ... FORCE will also fail if the view definition names a constraint that does not exist. (Enhencements on 10g)
scott@9ir2>select * from v$version;
BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
PL/SQL Release 9.2.0.1.0 - Production
CORE 9.2.0.1.0 Production
TNS for Compaq Tru64 UNIX: Version 9.2.0.1.0 - Production
NLSRTL Version 9.2.0.1.0 - Production
scott@9ir2>desc xyz
ERROR:
ORA-04043: object xyz does not exist
scott@9ir2>CREATE FORCE VIEW view_force AS SELECT * FROM xyz;
Warning: View created with compilation errors.
scott@9ir2>select VIEW_NAME, TEXT from user_views where VIEW_NAME = 'VIEW_FORCE';
VIEW_NAME
------------------------------
TEXT
--------------------------------------------------------------------------------
VIEW_FORCE
SELECT * FROM xyz
scott@9ir2>select * from view_force;
select * from view_force
*
ERROR at line 1:
ORA-04063: view "SCOTT.VIEW_FORCE" has errors
scott@9ir2>drop view view_force;
View dropped.
scott@9ir2>select VIEW_NAME, TEXT from user_views where VIEW_NAME = 'VIEW_FORCE';
no rows selected
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