Although the constraint attribute syntax provides 11 permutations
    as required by the SQL99 standard, they equate to the following
    three options:

    o  INITIALLY IMMEDIATE NOT DEFERRABLE

       Specifies that evaluation of the constraint must take place
       when the INSERT, DELETE, or UPDATE statement executes. If
       you are using the SQL99, SQL92, MIA, ORACLE LEVEL1, or ORACLE
       LEVEL2 dialect, this is the default.

    o  INITIALLY IMMEDIATE DEFERRABLE

       Specifies that evaluation of the constraint may be deferred
       (using the SET CONSTRAINT ALL statement or the SET TRANSACTION
       statement with the EVALUATING clause), but by default it
       is evaluated after the INSERT, DELETE, or UPDATE statement
       executes. See the SET_ALL_CONSTRAINTS statement for more
       information.

    o  INITIALLY DEFERRED DEFERRABLE

       Specifies that evaluation of the constraint can take place
       at any later time. Unless otherwise specified, evaluation of
       the constraint takes place as the COMMIT statement executes.
       You can use the SET ALL CONSTRAINTS statement to have all
       constraints evaluated earlier. See the description of the SET
       ALL CONSTRAINTS statement for more information.

       If you are using the default SQLV40 dialect, this is the
       default constraint attribute. When using this dialect, Oracle
       Rdb displays a deprecated feature message for all constraints
       defined without specification of one of the constraint
       attributes.