PostgreSQL Source Code: src/include/catalog/pg_cast.h Source File

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pg_cast.h
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1/*-------------------------------------------------------------------------
2 *
3 * pg_cast.h
4 * definition of the "type casts" system catalog (pg_cast)
5 *
6 * As of Postgres 8.0, pg_cast describes not only type coercion functions
7 * but also length coercion functions.
8 *
9 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
10 * Portions Copyright (c) 1994, Regents of the University of California
11 *
12 * src/include/catalog/pg_cast.h
13 *
14 * NOTES
15 * The Catalog.pm module reads this file and derives schema
16 * information.
17 *
18 *-------------------------------------------------------------------------
19 */
20#ifndef PG_CAST_H
21#define PG_CAST_H
22
23#include "catalog/dependency.h"
24#include "catalog/genbki.h"
25#include "catalog/pg_cast_d.h" /* IWYU pragma: export */
26
27/* ----------------
28 * pg_cast definition. cpp turns this into
29 * typedef struct FormData_pg_cast
30 * ----------------
31 */
32 CATALOG(pg_cast,2605,CastRelationId)
33{
34 Oid oid; /* oid */
35
36 /* source datatype for cast */
37 Oid castsource BKI_LOOKUP(pg_type);
38
39 /* destination datatype for cast */
40 Oid casttarget BKI_LOOKUP(pg_type);
41
42 /* cast function; 0 = binary coercible */
43 Oid castfunc BKI_LOOKUP_OPT(pg_proc);
44
45 /* contexts in which cast can be used */
46 char castcontext;
47
48 /* cast method */
49 char castmethod;
50 } FormData_pg_cast;
51
52/* ----------------
53 * Form_pg_cast corresponds to a pointer to a tuple with
54 * the format of pg_cast relation.
55 * ----------------
56 */
57 typedef FormData_pg_cast *Form_pg_cast;
58
59 DECLARE_UNIQUE_INDEX_PKEY(pg_cast_oid_index, 2660, CastOidIndexId, pg_cast, btree(oid oid_ops));
60 DECLARE_UNIQUE_INDEX(pg_cast_source_target_index, 2661, CastSourceTargetIndexId, pg_cast, btree(castsource oid_ops, casttarget oid_ops));
61
62 MAKE_SYSCACHE(CASTSOURCETARGET, pg_cast_source_target_index, 256);
63
64#ifdef EXPOSE_TO_CLIENT_CODE
65
66/*
67 * The allowable values for pg_cast.castcontext are specified by this enum.
68 * Since castcontext is stored as a "char", we use ASCII codes for human
69 * convenience in reading the table. Note that internally to the backend,
70 * these values are converted to the CoercionContext enum (see primnodes.h),
71 * which is defined to sort in a convenient order; the ASCII codes don't
72 * have to sort in any special order.
73 */
74
75typedef enum CoercionCodes
76{
77 COERCION_CODE_IMPLICIT = 'i', /* coercion in context of expression */
78 COERCION_CODE_ASSIGNMENT = 'a', /* coercion in context of assignment */
79 COERCION_CODE_EXPLICIT = 'e', /* explicit cast operation */
80} CoercionCodes;
81
82/*
83 * The allowable values for pg_cast.castmethod are specified by this enum.
84 * Since castmethod is stored as a "char", we use ASCII codes for human
85 * convenience in reading the table.
86 */
87typedef enum CoercionMethod
88{
89 COERCION_METHOD_FUNCTION = 'f', /* use a function */
90 COERCION_METHOD_BINARY = 'b', /* types are binary-compatible */
91 COERCION_METHOD_INOUT = 'i', /* use input/output functions */
92} CoercionMethod;
93
94#endif /* EXPOSE_TO_CLIENT_CODE */
95
96
97extern ObjectAddress CastCreate(Oid sourcetypeid,
98 Oid targettypeid,
99 Oid funcid,
100 Oid incastid,
101 Oid outcastid,
102 char castcontext,
103 char castmethod,
104 DependencyType behavior);
105
106#endif /* PG_CAST_H */
DependencyType
Definition: dependency.h:32
#define BKI_LOOKUP(catalog)
Definition: genbki.h:46
#define BKI_LOOKUP_OPT(catalog)
Definition: genbki.h:47
CATALOG(pg_cast, 2605, CastRelationId)
Definition: pg_cast.h:32
DECLARE_UNIQUE_INDEX_PKEY(pg_cast_oid_index, 2660, CastOidIndexId, pg_cast, btree(oid oid_ops))
DECLARE_UNIQUE_INDEX(pg_cast_source_target_index, 2661, CastSourceTargetIndexId, pg_cast, btree(castsource oid_ops, casttarget oid_ops))
ObjectAddress CastCreate(Oid sourcetypeid, Oid targettypeid, Oid funcid, Oid incastid, Oid outcastid, char castcontext, char castmethod, DependencyType behavior)
Definition: pg_cast.c:49
MAKE_SYSCACHE(CASTSOURCETARGET, pg_cast_source_target_index, 256)
FormData_pg_cast * Form_pg_cast
Definition: pg_cast.h:57
FormData_pg_cast
Definition: pg_cast.h:50
unsigned int Oid
Definition: postgres_ext.h:32

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