SQL How to Alter Constraint
Below is 1 of my constraint
CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode),
I want to add in
ON DELETE CASCADE
to the constraint above.
How do i alter that existing constraint ACTIVEPROG_FKEY1 and add
ON DELETE CASCADE
to constraint ACTIVEPROG_FKEY1
Consider ACTIVEPROG_FKEY1 is at Table ACTIVEPROG
You can not alter constraints ever but you can drop them and then recreate.
Have look on this
ALTER TABLE your_table DROP CONSTRAINT ACTIVEPROG_FKEY1;
and then recreate it with ON DELETE CASCADE like this
ALTER TABLE your_table
add CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode)
ON DELETE CASCADE;
hope this help
No. We cannot alter the constraint, only thing we can do is drop and recreate it
ALTER TABLE [TABLENAME] DROP CONSTRAINT [CONSTRAINTNAME]
Foreign Key Constraint
Alter Table Table1 Add Constraint [CONSTRAINTNAME] Foreign Key (Column) References Table2 (Column) On Update Cascade On Delete Cascade
Primary Key constraint
Alter Table Table add constraint [Primary Key] Primary key(Column1,Column2,.....)
Source: Stackoverflow.com