The RDB$PARAMETERS system table defines the routine interface for
    each routine stored in RDB$ROUTINES. Each parameter to a routine
    (procedure or function) is described by a row in RDB$PARAMETERS.
    The following table provides information on the columns of the
    RDB$PARAMETERS system table.

                                Data
    Column Name                 Type      Summary Description

    RDB$PARAMETER_NAME          char(31)  Name of the parameter.
    RDB$PARAMETER_SOURCE        char(31)  Source (domain or table) to
                                          the routine containing the
                                          parameter.
    RDB$ROUTINE_ID              integer   Unique identifier assigned
                                          to the routine containing
                                          this parameter by Oracle
                                          Rdb.
    RDB$ORDINAL_POSITION        integer   Position in parameter
                                          list. Position 0
                                          indicates function result
                                          description.
    RDB$PARAMETER_TYPE          integer   Data type of the parameter.
    RDB$PARAMETER_SUB_TYPE      integer   A value that describes
                                          the data subtype of
                                          RDB$PARAMETER_TYPE as shown
                                          in RDB$FIELD_SUB_TYPE Help
                                          topic.
    RDB$PARAMETER_LENGTH        integer   Length of the parameter.
    RDB$PARAMETER_SCALE         integer   Scale of the data type.
    RDB$PARAMETER_SEG_LENGTH    integer   The length of the segmented
                                          string segment. For date-
                                          time interval fields, the
                                          interval leading field
                                          precision.
    RDB$DEFAULT_VALUE2          list      Parameter default.
                                of byte
                                varying
    RDB$FLAGS                   integer   Flags.
    RDB$DESCRIPTION             list      Description of the
                                of byte   parameter.
                                varying
    RDB$SECURITY_CLASS          char(20)  Reserved for future use.

1  –  RDB$FLAGS

    Represents flags for RDB$PARAMETERS system table.

    Bit
    Position   Description

    0          IN (read) INOUT (modify).
    1          OUT (write) INOUT (modify).
    2          Reserved for future use.
    3          BY DESCRIPTOR (default is BY REFERENCE).
    4          BY VALUE (Bit number 3 is ignored).
    5          Reserved for future use.
    6          Set if parameter mode is undefined.
               If Bits 0 and 1 are both clear, then the parameter is
               the RETURN TYPE of a function.