|
By default, constraints are non-transitional and all transition properties have the empty value.
You can turn a constraint into a transitional constraint by setting transition properties, or by using the OLD() function in the constraint SQL statements, or both.
Transition Property
|
Value
|
Meaning
|
Transition Table
|
|
Table for which the constraint is evaluated.
|
Alias
|
|
Alias identifying the table occurrence in the SQL statement for which the constraint is evaluated (if the table name is mentioned more than one time in the statement). For Example:
Transition Table: TOUR, Alias: T2
|
Fire on Insert
|
Always
|
Constraint is evaluated for each record being inserted into the transition table.
|
|
Never
|
Constraint is not evaluated when records are inserted into the transition table.
|
Fire on Delete
|
Always
|
Constraint is evaluated for each record being deleted from the transition table.
|
|
Never
|
Constraint is not evaluated when records are deleted from the transition table.
|
Fire on Update
|
Always
|
Constraint is evaluated whenever UPDATE manipulations occur on any of the columns of the transition table.Always: Constraint is evaluated whenever UPDATE manipulations occur on any of the columns of the transition table.
|
|
UsedColumns
|
Constraint is evaluated whenever UPDATE manipulations occur on one or more of the columns of the transition table appearing in the constraint.
|
|
Never
|
Constraint is not evaluated when records are updated in the transition table.
|
See also
Default transition properties
Changing default transition properties
Transitional constraints without OLD()
|
