sql - Database Meaning of one Constraint -

sql - Database Meaning of one Constraint -

anyone describe me meaning of qty > qty(500) in next sentence?

constraint dbc1 is_empty ((s bring together sp) status<20 , qty>qty(500));

i translate it: status lower 20 , quantity bigger 500.

please note need meaning of qty> qty(500)...

(s bring together sp) contains tuple each shipment, , tuple "extended" details of supplier, such status code.

the [result of restriction defined the] clause amounts "shipments of quantity >500 corresponding supplier's status <20".

the declaration overall says "there cannot shipments of quantity >500 corresponding supplier's status <20.

sql database database-design relational-database database-schema