The DEFINE COLLATING_SEQUENCE statement identifies a collating
    sequence that has been defined using the OpenVMS National
    Character Set (NCS) Utility. Use the DEFINE COLLATING_SEQUENCE
    statement to identify collating sequences other than the database
    default collating sequence that you plan to use with certain
    global fields. (The default collating sequence for a database
    is established by the COLLATING_SEQUENCE IS clause in the
    DEFINE DATABASE statement; if you omit that clause at database
    definition time, the default sequence is ASCII.)

    You must enter a DEFINE COLLATING_SEQUENCE statement specifying a
    collating sequence before you enter the name of that sequence in
    any of the following statements:

    o  DEFINE FIELD...COLLATING_SEQUENCE

    o  CHANGE FIELD...COLLATING_SEQUENCE

    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.

    Other users are allowed to be attached to the database when you
    issue the DEFINE COLLATING_SEQUENCE statement.