|
See
Also
By default, constraints are
non-transitional and all transition properties have no value. In
contrast, transitional constraints have transition properties with
default or specified values.
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.
This table lists the
transition properties and their meaning:
Transition Properties
|
Transition Property
|
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 never
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 never
evaluated when records are deleted from the transition table.
|
|
Fire on Update
|
Used Columns: Constraint is evaluated whenever UPDATE
manipulations occur on one or more of the columns of the transition
table appearing in the constraint.
Always: Constraint is
evaluated whenever UPDATE manipulations occur on any of the columns
of the transition table.
Never: Constraint is never
evaluated when records are updated in the transition table.
|
Related Topics
Default Transition
Properties
Resetting Default
Transition Properties
Transitional
Constraints Without OLD()
|
