Using the field-constraint-def clause you can name or specify the
type of field-level constraints to be defined within a specific
relation definition.
(B)0[mfield-constraint-def =
qwqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqwqk
mq> [4mCONSTRAINT[m constraint-name IS qqj x
lqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqj
mwq> [4mNOT[m [4mMISSING[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqwqk
tq> [4mUNIQUE[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqu x
tq> [4mPRIMARY[m [4mKEY[m qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqu x
mw> [4mREFERENCES[m referenced-relation-name qwqqqqqqqqqqqqqqqqqqqqqqqqwu x
x m> referenced-field-name jx x
x x x
mq> [4mUSING[m rse [4mREQUIRE[m conditional-expr qqqqqqqqqqqq>qqqqqqqqqqqqqqj x
x
lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq<qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
mwqqqqqqqqqqqqqqqqqqqqqqqqqqqwq>
mqq> [4mCHECK[m ON qwqq> [4mCOMMIT[m qu
mqq> [4mUPDATE[m qj
1 – Arguments
Constraint-name must be unique within the database. The
constraint name can be referred to in other statements such as
DEFINE RELATION, SHOW CONSTRAINT, and START_TRANSACTION.
The phrase 'CONSTRAINT constraint-name is' is optional. If you
specify the keyword CONSTRAINT, you must also provide a name for
the constraint.
A field constraint definition differs from a relation constraint
definition in that you cannot repeat referenced field names. See
the "relation-constraint-def" help subtopic of CHANGE_RELATION
for more information.