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Diffstat (limited to 'src/include/access/tupdesc.h')
| -rw-r--r-- | src/include/access/tupdesc.h | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/include/access/tupdesc.h b/src/include/access/tupdesc.h new file mode 100644 index 0000000..f45d47a --- /dev/null +++ b/src/include/access/tupdesc.h @@ -0,0 +1,154 @@ +/*------------------------------------------------------------------------- + * + * tupdesc.h + * POSTGRES tuple descriptor definitions. + * + * + * Portions Copyright (c) 1996-2021, 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 tupdesc); + +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 */ |