What is the use for CREATING VIEW WITH CHECK OPTION?

Question

Dear Legends,
I have a doubt
What is the use for creating view?
A: First Data Integrity, Selecting Particular Columns..
What is the use for creating a view with check option?
A: As per oracle manual I read that its a referential integrity check through views.
A: Enforcing constraints at DB level.
A: using CHECK OPTION we can do INSERTS UPDATES for a view for those columns who have no constraints... is it right??
A: If we do a INSERT OR UPDATE for columns who have constraints it will show error... is it right???
Please clear my doubt's Legends
Lots of Thanks....
Regards,
Karthik

Answer 1

Hi, Karthick,
karthiksingh_dba wrote:
... What is the use for creating view?
A: First Data Integrity, Selecting Particular Columns..Most views are created and used for convenience. A view is a saved query. If the same operations are often done, then it can be very convenient to code those operations once, in a view, and refer to the view rather than explicitly doing those operations.
Sometimes, views are created and used for security reasons. For example, you many want to allow some users to see only certain rows or certain columns of a table.
Views are necessary for INSTEAD OF triggers.
What is the use for creating a view with check option?
A: As per oracle manual I read that its a referential integrity check through views.The reason is integrity, not necessarily referential integrity. The CHECK option applies only when DML is done through the view. It prohibits certain changes. For example, if a user can't see certain rows through a view, the CHECK option keeps the user from creating such rows.
A: Enforcing constraints at DB level.I'm not sure what you mean. Please give an example.
A: using CHECK OPTION we can do INSERTS UPDATES for a view for those columns who have no constraints... is it right??No. Using CHECK OPTION, you can do some inserts and updates, but not others. The columns involved may or may not have constraints in either case.
A: If we do a INSERT OR UPDATE for columns who have constraints it will show error... is it right???If you try to violate a constraint, you'll get an error. That happens in views with or without the CHECK OPTION, and also in tables.