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 SQL92, SQL99, MIA, ORACLE LEVEL1 or ORACLE
       LEVEL2 dialect, this is the default.

       This clause is the same as the NOT DEFERRABLE option provided
       in previous releases of Oracle Rdb.

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

       This clause is the same as the DEFERRABLE option provided in
       previous releases of Oracle Rdb.

    o  INITIALLY IMMEDIATE DEFERRABLE

       Specifies that evaluation of the constraint 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.