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/*-------------------------------------------------------------------------
*
* tupdesc.h
* POSTGRES tuple descriptor definitions.
*
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/tupdesc.h
*
*-------------------------------------------------------------------------
*/
#ifndef TUPDESC_H
#define TUPDESC_H
#include "access/attnum.h"
#include "catalog/pg_attribute.h"
#include "nodes/pg_list.h"
typedef struct AttrDefault
{
AttrNumber adnum;
char *adbin; /* nodeToString representation of expr */
} AttrDefault;
typedef struct ConstrCheck
{
char *ccname;
char *ccbin; /* nodeToString representation of expr */
bool ccvalid;
bool ccnoinherit; /* this is a non-inheritable constraint */
} ConstrCheck;
/* This structure contains constraints of a tuple */
typedef struct TupleConstr
{
AttrDefault *defval; /* array */
ConstrCheck *check; /* array */
struct AttrMissing *missing; /* missing attributes values, NULL if none */
uint16 num_defval;
uint16 num_check;
bool has_not_null;
bool has_generated_stored;
} TupleConstr;
/*
* This struct is passed around within the backend to describe the structure
* of tuples. For tuples coming from on-disk relations, the information is
* collected from the pg_attribute, pg_attrdef, and pg_constraint catalogs.
* Transient row types (such as the result of a join query) have anonymous
* TupleDesc structs that generally omit any constraint info; therefore the
* structure is designed to let the constraints be omitted efficiently.
*
* Note that only user attributes, not system attributes, are mentioned in
* TupleDesc.
*
* If the tupdesc is known to correspond to a named rowtype (such as a table's
* rowtype) then tdtypeid identifies that type and tdtypmod is -1. Otherwise
* tdtypeid is RECORDOID, and tdtypmod can be either -1 for a fully anonymous
* row type, or a value >= 0 to allow the rowtype to be looked up in the
* typcache.c type cache.
*
* Note that tdtypeid is never the OID of a domain over composite, even if
* we are dealing with values that are known (at some higher level) to be of
* a domain-over-composite type. This is because tdtypeid/tdtypmod need to
* match up with the type labeling of composite Datums, and those are never
* explicitly marked as being of a domain type, either.
*
* Tuple descriptors that live in caches (relcache or typcache, at present)
* are reference-counted: they can be deleted when their reference count goes
* to zero. Tuple descriptors created by the executor need no reference
* counting, however: they are simply created in the appropriate memory
* context and go away when the context is freed. We set the tdrefcount
* field of such a descriptor to -1, while reference-counted descriptors
* always have tdrefcount >= 0.
*/
typedef struct TupleDescData
{
int natts; /* number of attributes in the tuple */
Oid tdtypeid; /* composite type ID for tuple type */
int32 tdtypmod; /* typmod for tuple type */
int tdrefcount; /* reference count, or -1 if not counting */
TupleConstr *constr; /* constraints, or NULL if none */
/* attrs[N] is the description of Attribute Number N+1 */
FormData_pg_attribute attrs[FLEXIBLE_ARRAY_MEMBER];
} TupleDescData;
typedef struct TupleDescData *TupleDesc;
/* Accessor for the i'th attribute of tupdesc. */
#define TupleDescAttr(tupdesc, i) (&(tupdesc)->attrs[(i)])
extern TupleDesc CreateTemplateTupleDesc(int natts);
extern TupleDesc CreateTupleDesc(int natts, Form_pg_attribute *attrs);
extern TupleDesc CreateTupleDescCopy(TupleDesc tupdesc);
extern TupleDesc CreateTupleDescCopyConstr(TupleDesc tupdesc);
#define TupleDescSize(src) \
(offsetof(struct TupleDescData, attrs) + \
(src)->natts * sizeof(FormData_pg_attribute))
extern void TupleDescCopy(TupleDesc dst, TupleDesc src);
extern void TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
TupleDesc src, AttrNumber srcAttno);
extern void FreeTupleDesc(TupleDesc tupdesc);
extern void IncrTupleDescRefCount(TupleDesc tupdesc);
extern void DecrTupleDescRefCount(TupleDesc tupdesc);
#define PinTupleDesc(tupdesc) \
do { \
if ((tupdesc)->tdrefcount >= 0) \
IncrTupleDescRefCount(tupdesc); \
} while (0)
#define ReleaseTupleDesc(tupdesc) \
do { \
if ((tupdesc)->tdrefcount >= 0) \
DecrTupleDescRefCount(tupdesc); \
} while (0)
extern bool equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
extern uint32 hashTupleDesc(TupleDesc desc);
extern void TupleDescInitEntry(TupleDesc desc,
AttrNumber attributeNumber,
const char *attributeName,
Oid oidtypeid,
int32 typmod,
int attdim);
extern void TupleDescInitBuiltinEntry(TupleDesc desc,
AttrNumber attributeNumber,
const char *attributeName,
Oid oidtypeid,
int32 typmod,
int attdim);
extern void TupleDescInitEntryCollation(TupleDesc desc,
AttrNumber attributeNumber,
Oid collationid);
extern TupleDesc BuildDescForRelation(List *schema);
extern TupleDesc BuildDescFromLists(List *names, List *types, List *typmods, List *collations);
#endif /* TUPDESC_H */
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