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pg_description.h
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1 /*-------------------------------------------------------------------------
2  *
3  * pg_description.h
4  * definition of the "description" system catalog (pg_description)
5  *
6  * Because the contents of this table are taken from the *.dat files
7  * of other catalogs, there is no pg_description.dat file. The initial
8  * contents are assembled by genbki.pl and loaded during initdb.
9  *
10  * NOTE: an object is identified by the OID of the row that primarily
11  * defines the object, plus the OID of the table that that row appears in.
12  * For example, a function is identified by the OID of its pg_proc row
13  * plus the pg_class OID of table pg_proc. This allows unique identification
14  * of objects without assuming that OIDs are unique across tables.
15  *
16  * Since attributes don't have OIDs of their own, we identify an attribute
17  * comment by the objoid+classoid of its parent table, plus an "objsubid"
18  * giving the attribute column number. "objsubid" must be zero in a comment
19  * for a table itself, so that it is distinct from any column comment.
20  * Currently, objsubid is unused and zero for all other kinds of objects,
21  * but perhaps it might be useful someday to associate comments with
22  * constituent elements of other kinds of objects (arguments of a function,
23  * for example).
24  *
25  *
26  * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
27  * Portions Copyright (c) 1994, Regents of the University of California
28  *
29  * src/include/catalog/pg_description.h
30  *
31  * NOTES
32  * The Catalog.pm module reads this file and derives schema
33  * information.
34  *
35  *-------------------------------------------------------------------------
36  */
37 #ifndef PG_DESCRIPTION_H
38 #define PG_DESCRIPTION_H
39 
40 #include "catalog/genbki.h"
41 #include "catalog/pg_description_d.h"
42 
43 /* ----------------
44  * pg_description definition. cpp turns this into
45  * typedef struct FormData_pg_description
46  * ----------------
47  */
48 CATALOG(pg_description,2609,DescriptionRelationId) BKI_WITHOUT_OIDS
49 {
50  Oid objoid; /* OID of object itself */
51  Oid classoid; /* OID of table containing object */
52  int32 objsubid; /* column number, or 0 if not used */
53 
54 #ifdef CATALOG_VARLEN /* variable-length fields start here */
55  text description BKI_FORCE_NOT_NULL; /* description of object */
56 #endif
58 
59 /* ----------------
60  * Form_pg_description corresponds to a pointer to a tuple with
61  * the format of pg_description relation.
62  * ----------------
63  */
65 
66 #endif /* PG_DESCRIPTION_H */
FormData_pg_description
unsigned int Oid
Definition: postgres_ext.h:31
signed int int32
Definition: c.h:313
#define BKI_WITHOUT_OIDS
Definition: genbki.h:28
#define BKI_FORCE_NOT_NULL
Definition: genbki.h:34
Oid classoid
Definition: pg_shseclabel.h:31
FormData_pg_description * Form_pg_description
Definition: c.h:516
CATALOG(pg_description, 2609, DescriptionRelationId) BKI_WITHOUT_OIDS