src/include/catalog/pg_description.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_description.h
   4  *        definition of the system "description" relation (pg_description)
   5  *
   6  * NOTE: an object is identified by the OID of the row that primarily
   7  * defines the object, plus the OID of the table that that row appears in.
   8  * For example, a function is identified by the OID of its pg_proc row
   9  * plus the pg_class OID of table pg_proc.      This allows unique identification
  10  * of objects without assuming that OIDs are unique across tables.
  11  *
  12  * Since attributes don't have OIDs of their own, we identify an attribute
  13  * comment by the objoid+classoid of its parent table, plus an "objsubid"
  14  * giving the attribute column number.  "objsubid" must be zero in a comment
  15  * for a table itself, so that it is distinct from any column comment.
  16  * Currently, objsubid is unused and zero for all other kinds of objects,
  17  * but perhaps it might be useful someday to associate comments with
  18  * constituent elements of other kinds of objects (arguments of a function,
  19  * for example).
  20  *
  21  *
  22  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  23  * Portions Copyright (c) 1994, Regents of the University of California
  24  *
  25  * $PostgreSQL$
  26  *
  27  * NOTES
  28  *              the genbki.sh script reads this file and generates .bki
  29  *              information from the DATA() statements.
  30  *
  31  *              XXX do NOT break up DATA() statements into multiple lines!
  32  *                      the scripts are not as smart as you might think...
  33  *
  34  *-------------------------------------------------------------------------
  35  */
  36 #ifndef PG_DESCRIPTION_H
  37 #define PG_DESCRIPTION_H
  38
  39 #include "catalog/genbki.h"
  40
  41 /* ----------------
  42  *              pg_description definition.      cpp turns this into
  43  *              typedef struct FormData_pg_description
  44  * ----------------
  45  */
  46 #define DescriptionRelationId  2609
  47
  48 CATALOG(pg_description,2609) BKI_WITHOUT_OIDS
  49 {
  50         Oid                     objoid;                 /* OID of object itself */
  51         Oid                     classoid;               /* OID of table containing object */
  52         int4            objsubid;               /* column number, or 0 if not used */
  53         text            description;    /* description of object */
  54 } FormData_pg_description;
  55
  56 /* ----------------
  57  *              Form_pg_description corresponds to a pointer to a tuple with
  58  *              the format of pg_description relation.
  59  * ----------------
  60  */
  61 typedef FormData_pg_description *Form_pg_description;
  62
  63 /* ----------------
  64  *              compiler constants for pg_description
  65  * ----------------
  66  */
  67 #define Natts_pg_description                    4
  68 #define Anum_pg_description_objoid              1
  69 #define Anum_pg_description_classoid    2
  70 #define Anum_pg_description_objsubid    3
  71 #define Anum_pg_description_description 4
  72
  73 /* ----------------
  74  *              initial contents of pg_description
  75  * ----------------
  76  */
  77
  78 /*
  79  *      Because the contents of this table are taken from the other *.h files,
  80  *      there is no initialization here.  The initial contents are extracted
  81  *      by genbki.sh and loaded during initdb.
  82  */
  83
  84 #endif   /* PG_DESCRIPTION_H */