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94aa7cc5f7
The SQL standard has been ambiguous about whether null values in
unique constraints should be considered equal or not. Different
implementations have different behaviors. In the SQL:202x draft, this
has been formalized by making this implementation-defined and adding
an option on unique constraint definitions UNIQUE [ NULLS [NOT]
DISTINCT ] to choose a behavior explicitly.
This patch adds this option to PostgreSQL. The default behavior
remains UNIQUE NULLS DISTINCT. Making this happen in the btree code
is pretty easy; most of the patch is just to carry the flag around to
all the places that need it.
The CREATE UNIQUE INDEX syntax extension is not from the standard,
it's my own invention.
I named all the internal flags, catalog columns, etc. in the negative
("nulls not distinct") so that the default PostgreSQL behavior is the
default if the flag is false.
Reviewed-by: Maxim Orlov <orlovmg@gmail.com>
Reviewed-by: Pavel Borisov <pashkin.elfe@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/84e5ee1b-387e-9a54-c326-9082674bde78@enterprisedb.com
110 lines
3.4 KiB
C
110 lines
3.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* makefuncs.h
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* prototypes for the creator functions of various nodes
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*
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*
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* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/nodes/makefuncs.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef MAKEFUNC_H
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#define MAKEFUNC_H
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#include "nodes/execnodes.h"
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#include "nodes/parsenodes.h"
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extern A_Expr *makeA_Expr(A_Expr_Kind kind, List *name,
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Node *lexpr, Node *rexpr, int location);
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extern A_Expr *makeSimpleA_Expr(A_Expr_Kind kind, char *name,
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Node *lexpr, Node *rexpr, int location);
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extern Var *makeVar(int varno,
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AttrNumber varattno,
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Oid vartype,
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int32 vartypmod,
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Oid varcollid,
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Index varlevelsup);
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extern Var *makeVarFromTargetEntry(int varno,
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TargetEntry *tle);
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extern Var *makeWholeRowVar(RangeTblEntry *rte,
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int varno,
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Index varlevelsup,
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bool allowScalar);
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extern TargetEntry *makeTargetEntry(Expr *expr,
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AttrNumber resno,
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char *resname,
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bool resjunk);
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extern TargetEntry *flatCopyTargetEntry(TargetEntry *src_tle);
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extern FromExpr *makeFromExpr(List *fromlist, Node *quals);
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extern Const *makeConst(Oid consttype,
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int32 consttypmod,
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Oid constcollid,
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int constlen,
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Datum constvalue,
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bool constisnull,
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bool constbyval);
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extern Const *makeNullConst(Oid consttype, int32 consttypmod, Oid constcollid);
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extern Node *makeBoolConst(bool value, bool isnull);
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extern Expr *makeBoolExpr(BoolExprType boolop, List *args, int location);
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extern Alias *makeAlias(const char *aliasname, List *colnames);
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extern RelabelType *makeRelabelType(Expr *arg, Oid rtype, int32 rtypmod,
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Oid rcollid, CoercionForm rformat);
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extern RangeVar *makeRangeVar(char *schemaname, char *relname, int location);
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extern TypeName *makeTypeName(char *typnam);
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extern TypeName *makeTypeNameFromNameList(List *names);
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extern TypeName *makeTypeNameFromOid(Oid typeOid, int32 typmod);
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extern ColumnDef *makeColumnDef(const char *colname,
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Oid typeOid, int32 typmod, Oid collOid);
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extern FuncExpr *makeFuncExpr(Oid funcid, Oid rettype, List *args,
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Oid funccollid, Oid inputcollid, CoercionForm fformat);
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extern FuncCall *makeFuncCall(List *name, List *args,
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CoercionForm funcformat, int location);
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extern Expr *make_opclause(Oid opno, Oid opresulttype, bool opretset,
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Expr *leftop, Expr *rightop,
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Oid opcollid, Oid inputcollid);
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extern Expr *make_andclause(List *andclauses);
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extern Expr *make_orclause(List *orclauses);
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extern Expr *make_notclause(Expr *notclause);
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extern Node *make_and_qual(Node *qual1, Node *qual2);
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extern Expr *make_ands_explicit(List *andclauses);
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extern List *make_ands_implicit(Expr *clause);
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extern IndexInfo *makeIndexInfo(int numattrs, int numkeyattrs, Oid amoid,
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List *expressions, List *predicates,
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bool unique, bool nulls_not_distinct, bool isready, bool concurrent);
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extern DefElem *makeDefElem(char *name, Node *arg, int location);
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extern DefElem *makeDefElemExtended(char *nameSpace, char *name, Node *arg,
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DefElemAction defaction, int location);
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extern GroupingSet *makeGroupingSet(GroupingSetKind kind, List *content, int location);
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extern VacuumRelation *makeVacuumRelation(RangeVar *relation, Oid oid, List *va_cols);
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#endif /* MAKEFUNC_H */
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