Viewing file:  pg_attribute.h (6.79 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*-------------------------------------------------------------------------
*
* pg_attribute.h
* definition of the system "attribute" relation (pg_attribute)
* along with the relation's initial contents.
*
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/catalog/pg_attribute.h
*
* NOTES
* the genbki.pl script reads this file and generates .bki
* information from the DATA() statements.
*
*-------------------------------------------------------------------------
*/
#ifndef PG_ATTRIBUTE_H
#define PG_ATTRIBUTE_H
#include "catalog/genbki.h"
/* ----------------
* pg_attribute definition. cpp turns this into
* typedef struct FormData_pg_attribute
*
* If you change the following, make sure you change the structs for
* system attributes in catalog/heap.c also.
* You may need to change catalog/genbki.pl as well.
* ----------------
*/
#define AttributeRelationId 1249
#define AttributeRelation_Rowtype_Id 75
CATALOG(pg_attribute,1249) BKI_BOOTSTRAP BKI_WITHOUT_OIDS BKI_ROWTYPE_OID(75) BKI_SCHEMA_MACRO
{
Oid attrelid; /* OID of relation containing this attribute */
NameData attname; /* name of attribute */
/*
* atttypid is the OID of the instance in Catalog Class pg_type that
* defines the data type of this attribute (e.g. int4). Information in
* that instance is redundant with the attlen, attbyval, and attalign
* attributes of this instance, so they had better match or Postgres will
* fail.
*/
Oid atttypid;
/*
* attstattarget is the target number of statistics datapoints to collect
* during VACUUM ANALYZE of this column. A zero here indicates that we do
* not wish to collect any stats about this column. A "-1" here indicates
* that no value has been explicitly set for this column, so ANALYZE
* should use the default setting.
*/
int4 attstattarget;
/*
* attlen is a copy of the typlen field from pg_type for this attribute.
* See atttypid comments above.
*/
int2 attlen;
/*
* attnum is the "attribute number" for the attribute: A value that
* uniquely identifies this attribute within its class. For user
* attributes, Attribute numbers are greater than 0 and not greater than
* the number of attributes in the class. I.e. if the Class pg_class says
* that Class XYZ has 10 attributes, then the user attribute numbers in
* Class pg_attribute must be 1-10.
*
* System attributes have attribute numbers less than 0 that are unique
* within the class, but not constrained to any particular range.
*
* Note that (attnum - 1) is often used as the index to an array.
*/
int2 attnum;
/*
* attndims is the declared number of dimensions, if an array type,
* otherwise zero.
*/
int4 attndims;
/*
* fastgetattr() uses attcacheoff to cache byte offsets of attributes in
* heap tuples. The value actually stored in pg_attribute (-1) indicates
* no cached value. But when we copy these tuples into a tuple
* descriptor, we may then update attcacheoff in the copies. This speeds
* up the attribute walking process.
*/
int4 attcacheoff;
/*
* atttypmod records type-specific data supplied at table creation time
* (for example, the max length of a varchar field). It is passed to
* type-specific input and output functions as the third argument. The
* value will generally be -1 for types that do not need typmod.
*/
int4 atttypmod;
/*
* attbyval is a copy of the typbyval field from pg_type for this
* attribute. See atttypid comments above.
*/
bool attbyval;
/*----------
* attstorage tells for VARLENA attributes, what the heap access
* methods can do to it if a given tuple doesn't fit into a page.
* Possible values are
* 'p': Value must be stored plain always
* 'e': Value can be stored in "secondary" relation (if relation
* has one, see pg_class.reltoastrelid)
* 'm': Value can be stored compressed inline
* 'x': Value can be stored compressed inline or in "secondary"
* Note that 'm' fields can also be moved out to secondary storage,
* but only as a last resort ('e' and 'x' fields are moved first).
*----------
*/
char attstorage;
/*
* attalign is a copy of the typalign field from pg_type for this
* attribute. See atttypid comments above.
*/
char attalign;
/* This flag represents the "NOT NULL" constraint */
bool attnotnull;
/* Has DEFAULT value or not */
bool atthasdef;
/* Is dropped (ie, logically invisible) or not */
bool attisdropped;
/* Has a local definition (hence, do not drop when attinhcount is 0) */
bool attislocal;
/* Number of times inherited from direct parent relation(s) */
int4 attinhcount;
/* attribute's collation */
Oid attcollation;
#ifdef CATALOG_VARLEN /* variable-length fields start here */
/* NOTE: The following fields are not present in tuple descriptors. */
/* Column-level access permissions */
aclitem attacl[1];
/* Column-level options */
text attoptions[1];
/* Column-level FDW options */
text attfdwoptions[1];
#endif
} FormData_pg_attribute;
/*
* ATTRIBUTE_FIXED_PART_SIZE is the size of the fixed-layout,
* guaranteed-not-null part of a pg_attribute row. This is in fact as much
* of the row as gets copied into tuple descriptors, so don't expect you
* can access fields beyond attcollation except in a real tuple!
*/
#define ATTRIBUTE_FIXED_PART_SIZE \
(offsetof(FormData_pg_attribute,attcollation) + sizeof(Oid))
/* ----------------
* Form_pg_attribute corresponds to a pointer to a tuple with
* the format of pg_attribute relation.
* ----------------
*/
typedef FormData_pg_attribute *Form_pg_attribute;
/* ----------------
* compiler constants for pg_attribute
* ----------------
*/
#define Natts_pg_attribute 21
#define Anum_pg_attribute_attrelid 1
#define Anum_pg_attribute_attname 2
#define Anum_pg_attribute_atttypid 3
#define Anum_pg_attribute_attstattarget 4
#define Anum_pg_attribute_attlen 5
#define Anum_pg_attribute_attnum 6
#define Anum_pg_attribute_attndims 7
#define Anum_pg_attribute_attcacheoff 8
#define Anum_pg_attribute_atttypmod 9
#define Anum_pg_attribute_attbyval 10
#define Anum_pg_attribute_attstorage 11
#define Anum_pg_attribute_attalign 12
#define Anum_pg_attribute_attnotnull 13
#define Anum_pg_attribute_atthasdef 14
#define Anum_pg_attribute_attisdropped 15
#define Anum_pg_attribute_attislocal 16
#define Anum_pg_attribute_attinhcount 17
#define Anum_pg_attribute_attcollation 18
#define Anum_pg_attribute_attacl 19
#define Anum_pg_attribute_attoptions 20
#define Anum_pg_attribute_attfdwoptions 21
/* ----------------
* initial contents of pg_attribute
*
* The initial contents of pg_attribute are generated at compile time by
* genbki.pl. Only "bootstrapped" relations need be included.
* ----------------
*/
#endif /* PG_ATTRIBUTE_H */
|