Question

Sales DateAcquired AcquisitionPrice AskingPrice DateSold SalesPrice Client ClientID Artwork LastName FirstName Street City State ZipPostalCode Country AreaCode PhoneNumber Email WorklD Title Copy Medium Description ArtistlD ClientiD Workid

Write one DDL statement to add ‘C_999’ as a new constraint in Sales. This constraint ensures that no sale has a SalesPrice value higher than AskingPrice value. This statement should only affect new Artwork WorkID Title Copy Medium Description ArtistID Client ClientID LastName FirstName Street City State ZipPostalCode Country AreaCode PhoneNumber Email Sales DateAcquired AcquisitionPrice AskingPrice DateSold SalesPrice ClientID WorkID rows inserted into Sales in the future but not existing rows. If constraint ‘C_999’ needs to be deleted from Sales now, what DDL statement would you execute?

Answer 1

All the tables have to be created first and data can be inserted.To add constraint to the table we have to alter the table and add constraint.

C_999 is the name of the constraint which is used to delete the constraint also.

-To add constraint

ALTER TABLE Sales
ADD CONSTRAINT C_999 CHECK (SalesPrice>AskingPrice);

-To delete the constraint.

ALTER TABLE Sales
DROP CONSTRAINT C_999;