Progress
Embedded SQL-92
Guide and Reference
Types of Integrity Constraints
These are the types of integrity constraints:
Optionally, you can name an integrity constraint, and refer to that name in other SQL-92 statements. The database assigns a constraint name if you do not specify one. Typically, application-defined constraint names are easier to manage. Database-defined names can be long, unwieldy, and might require look-up in a system catalog.
EXAMPLEThe following code fragment shows the specification of a table constraint named prim_constr on the supplier_item table. You specify a constraint name with the CONSTRAINT keyword:
CREATE TABLE supplier_item (
supp_no INTEGER NOT NULL,
item_no INTEGER NOT NULL,
qty INTEGER NOT NULL DEFAULT 0
CONSTRAINT prim_constr
PRIMARY KEY (supp_no, item_no)
) ;
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