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/*-------------------------------------------------------------------------
*
* pg_description.h
* definition of the "description" system catalog (pg_description)
*
* Because the contents of this table are taken from the *.dat files
* of other catalogs, there is no pg_description.dat file. The initial
* contents are assembled by genbki.pl and loaded during initdb.
*
* NOTE: an object is identified by the OID of the row that primarily
* defines the object, plus the OID of the table that that row appears in.
* For example, a function is identified by the OID of its pg_proc row
* plus the pg_class OID of table pg_proc. This allows unique identification
* of objects without assuming that OIDs are unique across tables.
*
* Since attributes don't have OIDs of their own, we identify an attribute
* comment by the objoid+classoid of its parent table, plus an "objsubid"
* giving the attribute column number. "objsubid" must be zero in a comment
* for a table itself, so that it is distinct from any column comment.
* Currently, objsubid is unused and zero for all other kinds of objects,
* but perhaps it might be useful someday to associate comments with
* constituent elements of other kinds of objects (arguments of a function,
* for example).
*
*
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/catalog/pg_description.h
*
* NOTES
* The Catalog.pm module reads this file and derives schema
* information.
*
*-------------------------------------------------------------------------
*/
#ifndef PG_DESCRIPTION_H
#define PG_DESCRIPTION_H
#include "catalog/genbki.h"
#include "catalog/pg_description_d.h"
/* ----------------
* pg_description definition. cpp turns this into
* typedef struct FormData_pg_description
* ----------------
*/
CATALOG(pg_description,2609,DescriptionRelationId)
{
Oid objoid; /* OID of object itself */
Oid classoid; /* OID of table containing object */
int32 objsubid; /* column number, or 0 if not used */
#ifdef CATALOG_VARLEN /* variable-length fields start here */
text description BKI_FORCE_NOT_NULL; /* description of object */
#endif
} FormData_pg_description;
/* ----------------
* Form_pg_description corresponds to a pointer to a tuple with
* the format of pg_description relation.
* ----------------
*/
typedef FormData_pg_description * Form_pg_description;
DECLARE_TOAST(pg_description, 2834, 2835);
DECLARE_UNIQUE_INDEX_PKEY(pg_description_o_c_o_index, 2675, DescriptionObjIndexId, on pg_description using btree(objoid oid_ops, classoid oid_ops, objsubid int4_ops));
/* We do not use BKI_LOOKUP here because it causes problems for genbki.pl */
DECLARE_FOREIGN_KEY((classoid), pg_class, (oid));
#endif /* PG_DESCRIPTION_H */
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