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/*-------------------------------------------------------------------------
*
* tupdesc.h
* POSTGRES tuple descriptor definitions.
*
*
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/tupdesc.h,v 1.47 2005/03/07 04:42:17 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#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 */
} ConstrCheck;
/* This structure contains constraints of a tuple */
typedef struct tupleConstr
{
AttrDefault *defval; /* array */
ConstrCheck *check; /* array */
uint16 num_defval;
uint16 num_check;
bool has_not_null;
} 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; with the exception that tdhasoid indicates if OID is present.
*
* 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.
*/
typedef struct tupleDesc
{
int natts; /* number of attributes in the tuple */
Form_pg_attribute *attrs;
/* attrs[N] is a pointer to the description of Attribute Number N+1 */
TupleConstr *constr; /* constraints, or NULL if none */
Oid tdtypeid; /* composite type ID for tuple type */
int32 tdtypmod; /* typmod for tuple type */
bool tdhasoid; /* tuple has oid attribute in its header */
} *TupleDesc;
extern TupleDesc CreateTemplateTupleDesc(int natts, bool hasoid);
extern TupleDesc CreateTupleDesc(int natts, bool hasoid,
Form_pg_attribute *attrs);
extern TupleDesc CreateTupleDescCopy(TupleDesc tupdesc);
extern TupleDesc CreateTupleDescCopyConstr(TupleDesc tupdesc);
extern void FreeTupleDesc(TupleDesc tupdesc);
extern bool equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
extern void TupleDescInitEntry(TupleDesc desc,
AttrNumber attributeNumber,
const char *attributeName,
Oid oidtypeid,
int32 typmod,
int attdim);
extern TupleDesc BuildDescForRelation(List *schema);
#endif /* TUPDESC_H */
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