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The DROP CONSTRAINT command is used to delete a UNIQUE, PRIMARY KEY, FOREIGN KEY, or CHECK constraint
The DROP CONSTRAINT command is used to delete
a UNIQUE, PRIMARY KEY, FOREIGN KEY, or CHECK constraint.
To drop a UNIQUE constraint, use the following SQL:
ALTER TABLE Persons
DROP CONSTRAINT UC_Person;
ALTER TABLE Persons
DROP INDEX UC_Person;
To drop a PRIMARY KEY constraint, use the following SQL:
ALTER TABLE Persons
DROP CONSTRAINT PK_Person;
ALTER TABLE Persons
DROP PRIMARY KEY;
To drop a FOREIGN KEY constraint, use the following SQL:
ALTER TABLE Orders
DROP CONSTRAINT FK_PersonOrder;
ALTER TABLE Orders
DROP FOREIGN KEY FK_PersonOrder;
To drop a CHECK constraint, use the following SQL:
ALTER TABLE Persons
DROP CONSTRAINT CHK_PersonAge;
ALTER TABLE Persons
DROP CHECK CHK_PersonAge;