NOT NULL Check Constrailts

Check constraints will stop particular sets of data from been added to a column in a table. One type of check constraints is the NOT NULL keyword when adding a column or creating a table.

note: With the NOT NULL keyword a system generated identifier is used so the name of the check constraint will be different through the SDLC (assuming entire physical database refresh is not completed.)

drop check constraint:
alter table t1 drop constraint c1;