mirror of
https://github.com/postgres/postgres.git
synced 2025-05-15 00:02:24 -04:00
7103ebb7aa
MERGE performs actions that modify rows in the target table using a source table or query. MERGE provides a single SQL statement that can conditionally INSERT/UPDATE/DELETE rows -- a task that would otherwise require multiple PL statements. For example, MERGE INTO target AS t USING source AS s ON t.tid = s.sid WHEN MATCHED AND t.balance > s.delta THEN UPDATE SET balance = t.balance - s.delta WHEN MATCHED THEN DELETE WHEN NOT MATCHED AND s.delta > 0 THEN INSERT VALUES (s.sid, s.delta) WHEN NOT MATCHED THEN DO NOTHING; MERGE works with regular tables, partitioned tables and inheritance hierarchies, including column and row security enforcement, as well as support for row and statement triggers and transition tables therein. MERGE is optimized for OLTP and is parameterizable, though also useful for large scale ETL/ELT. MERGE is not intended to be used in preference to existing single SQL commands for INSERT, UPDATE or DELETE since there is some overhead. MERGE can be used from PL/pgSQL. MERGE does not support targetting updatable views or foreign tables, and RETURNING clauses are not allowed either. These limitations are likely fixable with sufficient effort. Rewrite rules are also not supported, but it's not clear that we'd want to support them. Author: Pavan Deolasee <pavan.deolasee@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Author: Amit Langote <amitlangote09@gmail.com> Author: Simon Riggs <simon.riggs@enterprisedb.com> Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com> Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions) Reviewed-by: Peter Geoghegan <pg@bowt.ie> (earlier versions) Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions) Reviewed-by: Japin Li <japinli@hotmail.com> Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Reviewed-by: Zhihong Yu <zyu@yugabyte.com> Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com Discussion: https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com Discussion: https://postgr.es/m/20201231134736.GA25392@alvherre.pgsql
125 lines
5.0 KiB
C
125 lines
5.0 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* parse_relation.h
|
|
* prototypes for parse_relation.c.
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* src/include/parser/parse_relation.h
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#ifndef PARSE_RELATION_H
|
|
#define PARSE_RELATION_H
|
|
|
|
#include "parser/parse_node.h"
|
|
|
|
|
|
extern ParseNamespaceItem *refnameNamespaceItem(ParseState *pstate,
|
|
const char *schemaname,
|
|
const char *refname,
|
|
int location,
|
|
int *sublevels_up);
|
|
extern CommonTableExpr *scanNameSpaceForCTE(ParseState *pstate,
|
|
const char *refname,
|
|
Index *ctelevelsup);
|
|
extern bool scanNameSpaceForENR(ParseState *pstate, const char *refname);
|
|
extern void checkNameSpaceConflicts(ParseState *pstate, List *namespace1,
|
|
List *namespace2);
|
|
extern ParseNamespaceItem *GetNSItemByRangeTablePosn(ParseState *pstate,
|
|
int varno,
|
|
int sublevels_up);
|
|
extern RangeTblEntry *GetRTEByRangeTablePosn(ParseState *pstate,
|
|
int varno,
|
|
int sublevels_up);
|
|
extern CommonTableExpr *GetCTEForRTE(ParseState *pstate, RangeTblEntry *rte,
|
|
int rtelevelsup);
|
|
extern Node *scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
|
|
int sublevels_up, const char *colname,
|
|
int location);
|
|
extern Node *colNameToVar(ParseState *pstate, const char *colname, bool localonly,
|
|
int location);
|
|
extern void markVarForSelectPriv(ParseState *pstate, Var *var);
|
|
extern Relation parserOpenTable(ParseState *pstate, const RangeVar *relation,
|
|
int lockmode);
|
|
extern ParseNamespaceItem *addRangeTableEntry(ParseState *pstate,
|
|
RangeVar *relation,
|
|
Alias *alias,
|
|
bool inh,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForRelation(ParseState *pstate,
|
|
Relation rel,
|
|
int lockmode,
|
|
Alias *alias,
|
|
bool inh,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForSubquery(ParseState *pstate,
|
|
Query *subquery,
|
|
Alias *alias,
|
|
bool lateral,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForFunction(ParseState *pstate,
|
|
List *funcnames,
|
|
List *funcexprs,
|
|
List *coldeflists,
|
|
RangeFunction *rangefunc,
|
|
bool lateral,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForValues(ParseState *pstate,
|
|
List *exprs,
|
|
List *coltypes,
|
|
List *coltypmods,
|
|
List *colcollations,
|
|
Alias *alias,
|
|
bool lateral,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForTableFunc(ParseState *pstate,
|
|
TableFunc *tf,
|
|
Alias *alias,
|
|
bool lateral,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForJoin(ParseState *pstate,
|
|
List *colnames,
|
|
ParseNamespaceColumn *nscolumns,
|
|
JoinType jointype,
|
|
int nummergedcols,
|
|
List *aliasvars,
|
|
List *leftcols,
|
|
List *rightcols,
|
|
Alias *joinalias,
|
|
Alias *alias,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForCTE(ParseState *pstate,
|
|
CommonTableExpr *cte,
|
|
Index levelsup,
|
|
RangeVar *rv,
|
|
bool inFromCl);
|
|
extern ParseNamespaceItem *addRangeTableEntryForENR(ParseState *pstate,
|
|
RangeVar *rv,
|
|
bool inFromCl);
|
|
extern bool isLockedRefname(ParseState *pstate, const char *refname);
|
|
extern void addNSItemToQuery(ParseState *pstate, ParseNamespaceItem *nsitem,
|
|
bool addToJoinList,
|
|
bool addToRelNameSpace, bool addToVarNameSpace);
|
|
extern void errorMissingRTE(ParseState *pstate, RangeVar *relation) pg_attribute_noreturn();
|
|
extern void errorMissingColumn(ParseState *pstate,
|
|
const char *relname, const char *colname, int location) pg_attribute_noreturn();
|
|
extern void expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
|
|
int location, bool include_dropped,
|
|
List **colnames, List **colvars);
|
|
extern List *expandNSItemVars(ParseNamespaceItem *nsitem,
|
|
int sublevels_up, int location,
|
|
List **colnames);
|
|
extern List *expandNSItemAttrs(ParseState *pstate, ParseNamespaceItem *nsitem,
|
|
int sublevels_up, bool require_col_privs,
|
|
int location);
|
|
extern int attnameAttNum(Relation rd, const char *attname, bool sysColOK);
|
|
extern const NameData *attnumAttName(Relation rd, int attid);
|
|
extern Oid attnumTypeId(Relation rd, int attid);
|
|
extern Oid attnumCollationId(Relation rd, int attid);
|
|
extern bool isQueryUsingTempRelation(Query *query);
|
|
|
|
#endif /* PARSE_RELATION_H */
|