Deletes one or more constraint definitions. When the DELETE
    CONSTRAINT statement executes, Oracle Rdb deletes the constraint
    definition from the physical database. If you use the PATHNAME
    argument when you invoke the database, DELETE CONSTRAINT also
    deletes the constraint definition from the data dictionary.

    You cannot delete a constraint when there are active transactions
    that access the relation or relations involved.

    You must execute this statement in a read/write transaction.
    If there is no active transaction and you issue this statement,
    Oracle Rdb starts a read/write transaction implicitly.

    You cannot delete a constraint definition unless you have invoked
    the database that includes the constraint. Other users are
    allowed to be attached to the database when you issue the DELETE
    CONSTRAINT statement.

    Example:

    DELETE CONSTRAINT EMPLOYEE_ID_EXISTS.

1  –  Format

  (B)0DELETE CONSTRAINT qqwqq> constraint-name qqwqq> .
                      mqqqqq<qqq , qqqq<qqqqqj

1.1  –  constraint-name

    The name of the constraint definition you want to delete.

2  –  Examples

    Example 1

    The following example deletes a single constraint definition:

    INVOKE DATABASE PATHNAME 'PERSONNEL'
    DELETE CONSTRAINT EMP_NUM_CON.

    This statement deletes EMP_NUM_CON from the physical database and
    the data dictionary.

    Example 2

    You can also delete more than one constraint definition at once:

    INVOKE DATABASE FILENAME 'PERSONNEL'
    DELETE CONSTRAINT SAL_CON,SS_NUM_CON.

    This statement deletes the two constraint definitions from the
    physical database.

3  –  More

    To delete a constraint, you must have the Oracle Rdb READ privilege
    to the database and the Oracle Rdb DELETE privilege to all relations
    to which the constraint refers.