The RDB$TRIGGERS system table describes the definition of a
    trigger. The following table provides information on the columns
    of the RDB$TRIGGERS system table.

                                Data
    Column Name                 Type      Summary Description

    RDB$DESCRIPTION             list      A user-supplied text string
                                of byte   describing the trigger.
                                varying
    RDB$FLAGS                   integer   Flags.
    RDB$RELATION_NAME           char(31)  The name of the table for
                                          which this trigger is
                                          defined. The trigger may
                                          be selected on an update to
                                          the named table (qualified
                                          by the columns described in
                                          the RDB$TRIGGER_FIELD_NAME_
                                          LIST).

                                          This table is used as a
                                          subject table for all
                                          contexts that refer to
                                          it.
    RDB$TRIGGER_ACTIONS         list      A text string containing
                                of byte   all the sets of triggered
                                varying   actions defined for this
                                          trigger. The string
                                          consists of one or more
                                          sets of clumplets, one set
                                          for each triggered action.
    RDB$TRIGGER_CONTEXTS        integer   The context number used
                                          within the triggered action
                                          BLR to map the triggered
                                          action BLR to the current
                                          context of the triggering
                                          update statement.
    RDB$TRIGGER_FIELD_NAME_     list      A text string composed of
    LIST                        of byte   a count field and one or
                                varying   more counted strings. The
                                          count is an unsigned word
                                          that represents the number
                                          of strings in the list.

                                          The counted strings
                                          are ASCIC names that
                                          represent column names.
                                          If the trigger is of event
                                          type UPDATE, it will be
                                          evaluated if one or more of
                                          the specified columns has
                                          been modified.
    RDB$TRIGGER_NAME            char(31)  The name of a trigger.
                                          This name must be a unique
                                          trigger name within the
                                          database.
    RDB$TRIGGER_NEW_CONTEXT     integer   A context number used
                                          within the triggered
                                          action's BLR to refer to
                                          the new row values for the
                                          subject table for an UPDATE
                                          event.
    RDB$TRIGGER_OLD_CONTEXT     integer   A context number used
                                          within the triggered
                                          action's BLR to refer to
                                          the old row values of the
                                          subject table that existed
                                          before an UPDATE event.
    RDB$TRIGGER_SOURCE          list      An optional text string for
                                of byte   the trigger definition. The
                                varying   string is not used by the
                                          database system.

                                          It should reflect the full
                                          definition of the trigger.
                                          This column is used by the
                                          interfaces to display the
                                          trigger definition.
    RDB$TRIGGER_TYPE            integer   The type of trigger, as
                                          defined by the combination
                                          of the trigger action time
                                          and the trigger event.
                                          Action times are BEFORE
                                          and AFTER, and events are
                                          INSERT, DELETE, and UPDATE.

                                          The values that represent
                                          the type of trigger are
                                          shown in the TRIGGER_TYPE_
                                          VAL Help topic.
    RDB$SECURITY_CLASS          char(20)  Reserved for future use.
    RDB$CREATED                 date vms  Set when the trigger is
                                          created.
    RDB$LAST_ALTERED            date vms  Set when SQL ALTER TRIGGER
                                          statement is used.
    RDB$TRIGGER_CREATOR         char(31)  Creator of this trigger.
    RDB$EXTENSION_PARAMETERS    list      Extension parameters.
                                of byte
                                varying