Search notes:
SQL: table constraints
A
table constraint
enforces an
integrity rule
on a
table
.
The
SQL standard
specifies four table constraints:
Primary key
constraint
Unique constraint
Referential constraint
Check Constraint
A table constraint is
either
enforced
or
not enforced
either
deferrable
or
not deferrable
See also
SQL Standard feature F383: Set column
not null
clause
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