From c59887f91618b95f42a33d4c62dac35165a7910a Mon Sep 17 00:00:00 2001 From: Neil Conway Date: Tue, 7 Jun 2005 02:47:23 +0000 Subject: [PATCH] Add support for an optional INTO clause to PL/PgSQL's EXECUTE command. This allows the result of executing a SELECT to be assigned to a row variable, record variable, or list of scalars. Docs and regression tests updated. Per Pavel Stehule, improvements and cleanup by Neil Conway. --- doc/src/sgml/plpgsql.sgml | 45 +++++++++++++----------- src/pl/plpgsql/src/gram.y | 49 +++++++++++++++++++++++++-- src/pl/plpgsql/src/pl_exec.c | 29 ++++++++++++++-- src/pl/plpgsql/src/plpgsql.h | 4 ++- src/test/regress/expected/plpgsql.out | 35 +++++++++++++++++++ src/test/regress/sql/plpgsql.sql | 32 +++++++++++++++++ 6 files changed, 169 insertions(+), 25 deletions(-) diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 7d2b37e41d..d96c123e21 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -1,5 +1,5 @@ @@ -1251,13 +1251,14 @@ NULL; EXECUTE statement is provided: -EXECUTE command-string; +EXECUTE command-string [ INTO target ]; where command-string is an expression - yielding a string (of type - text) containing the command - to be executed. This string is fed literally to the SQL engine. + yielding a string (of type text) containing the + command to be executed and target is a + record variable, row variable, or a comma-separated list of + simple variables and record/row fields. @@ -1276,16 +1277,22 @@ EXECUTE command-string; - The results from SELECT commands are discarded - by EXECUTE, and SELECT INTO - is not currently supported within EXECUTE. - So there is no way to extract a result from a dynamically-created - SELECT using the plain EXECUTE - command. There are two other ways to do it, however: one is to use the - FOR-IN-EXECUTE - loop form described in , - and the other is to use a cursor with OPEN-FOR-EXECUTE, as - described in . + The INTO clause specifies where the results of + a SELECT command should be assigned. If a row + or variable list is provided, it must exactly match the structure + of the results produced by the SELECT (when a + record variable is used, it will configure itself to match the + result's structure automatically). If multiple rows are returned, + only the first will be assigned to the INTO + variable. If no rows are returned, NULL is assigned to the + INTO variable. If no INTO + clause is specified, the results of a SELECT + command are discarded. + + + + SELECT INTO is not currently supported within + EXECUTE. @@ -1364,7 +1371,7 @@ EXECUTE 'UPDATE tbl SET ' command, which has the form: -GET DIAGNOSTICS variable = item , ... ; +GET DIAGNOSTICS variable = item , ... ; This command allows retrieval of system status indicators. Each @@ -2173,7 +2180,7 @@ SELECT merge_db (1, 'dennis'); Another way is to use the cursor declaration syntax, which in general is: -name CURSOR ( arguments ) FOR query ; +name CURSOR ( arguments ) FOR query; (FOR may be replaced by IS for Oracle compatibility.) @@ -2218,7 +2225,7 @@ DECLARE <command>OPEN FOR</command> <replaceable>query</replaceable> -OPEN unbound_cursor FOR query ; +OPEN unbound_cursor FOR query; @@ -3188,7 +3195,7 @@ DECLARE func_body text; func_cmd text; BEGIN - func_body := 'BEGIN' ; + func_body := 'BEGIN'; -- Notice how we scan through the results of a query in a FOR loop -- using the FOR <record> construct. diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y index 028323192f..d1823d7a09 100644 --- a/src/pl/plpgsql/src/gram.y +++ b/src/pl/plpgsql/src/gram.y @@ -4,7 +4,7 @@ * procedural language * * IDENTIFICATION - * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.72 2005/05/26 04:08:31 momjian Exp $ + * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.73 2005/06/07 02:47:16 neilc Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -1250,19 +1250,62 @@ stmt_execsql : execsql_start lno } ; -stmt_dynexecute : K_EXECUTE lno expr_until_semi +stmt_dynexecute : K_EXECUTE lno { PLpgSQL_stmt_dynexecute *new; + PLpgSQL_expr *expr; + int endtoken; + + expr = read_sql_construct(K_INTO, ';', "INTO|;", "SELECT ", + true, true, &endtoken); new = palloc(sizeof(PLpgSQL_stmt_dynexecute)); new->cmd_type = PLPGSQL_STMT_DYNEXECUTE; new->lineno = $2; - new->query = $3; + new->query = expr; + + new->rec = NULL; + new->row = NULL; + + /* + * If we saw "INTO", look for an additional + * row or record var. + */ + if (endtoken == K_INTO) + { + switch (yylex()) + { + case T_ROW: + check_assignable((PLpgSQL_datum *) yylval.row); + new->row = yylval.row; + break; + + case T_RECORD: + check_assignable((PLpgSQL_datum *) yylval.row); + new->rec = yylval.rec; + break; + + case T_SCALAR: + new->row = read_into_scalar_list(yytext, yylval.scalar); + break; + + default: + plpgsql_error_lineno = $2; + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("syntax error at \"%s\"", + yytext), + errdetail("Expected record or row variable."))); + } + if (yylex() != ';') + yyerror("syntax error"); + } $$ = (PLpgSQL_stmt *)new; } ; + stmt_open : K_OPEN lno cursor_varptr { PLpgSQL_stmt_open *new; diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index 3c6216a3e5..1fe1ed4cbe 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -3,7 +3,7 @@ * procedural language * * IDENTIFICATION - * $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.141 2005/05/26 04:08:31 momjian Exp $ + * $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.142 2005/06/07 02:47:17 neilc Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -2202,6 +2202,13 @@ exec_stmt_dynexecute(PLpgSQL_execstate *estate, Oid restype; char *querystr; int exec_res; + PLpgSQL_rec *rec = NULL; + PLpgSQL_row *row = NULL; + + if (stmt->rec != NULL) + rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->recno]); + else if (stmt->row != NULL) + row = (PLpgSQL_row *) (estate->datums[stmt->row->rowno]); /* * First we evaluate the string expression after the EXECUTE keyword. @@ -2221,9 +2228,27 @@ exec_stmt_dynexecute(PLpgSQL_execstate *estate, /* * Call SPI_execute() without preparing a saved plan. The returncode can * be any standard OK. Note that while a SELECT is allowed, its - * results will be discarded. + * results will be discarded unless an INTO clause is specified. */ exec_res = SPI_execute(querystr, estate->readonly_func, 0); + + /* Assign to INTO variable */ + if (rec || row) + { + if (exec_res != SPI_OK_SELECT) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("EXECUTE ... INTO is only for SELECT"))); + else + { + if (SPI_processed == 0) + exec_move_row(estate, rec, row, NULL, SPI_tuptable->tupdesc); + else + exec_move_row(estate, rec, row, + SPI_tuptable->vals[0], SPI_tuptable->tupdesc); + } + } + switch (exec_res) { case SPI_OK_SELECT: diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h index 17a466e01e..a70553ac2c 100644 --- a/src/pl/plpgsql/src/plpgsql.h +++ b/src/pl/plpgsql/src/plpgsql.h @@ -3,7 +3,7 @@ * procedural language * * IDENTIFICATION - * $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.60 2005/05/26 04:08:31 momjian Exp $ + * $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.61 2005/06/07 02:47:18 neilc Exp $ * * This software is copyrighted by Jan Wieck - Hamburg. * @@ -524,6 +524,8 @@ typedef struct { /* Dynamic SQL string to execute */ int cmd_type; int lineno; + PLpgSQL_rec *rec; /* INTO record or row variable */ + PLpgSQL_row *row; PLpgSQL_expr *query; } PLpgSQL_stmt_dynexecute; diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out index 08fbe46b3a..39e61e09cf 100644 --- a/src/test/regress/expected/plpgsql.out +++ b/src/test/regress/expected/plpgsql.out @@ -2380,3 +2380,38 @@ ERROR: control reached end of function without RETURN CONTEXT: PL/pgSQL function "missing_return_expr" drop function void_return_expr(); drop function missing_return_expr(); +-- +-- EXECUTE ... INTO test +-- +create table eifoo (i integer, y integer); +create type eitype as (i integer, y integer); +create or replace function execute_into_test(varchar) returns record as $$ +declare + _r record; + _rt eifoo%rowtype; + _v eitype; + i int; + j int; + k int; +begin + execute 'insert into '||$1||' values(10,15)'; + execute 'select (row).* from (select row(10,1)::eifoo) s' into _r; + raise notice '% %', _r.i, _r.y; + execute 'select * from '||$1||' limit 1' into _rt; + raise notice '% %', _rt.i, _rt.y; + execute 'select *, 20 from '||$1||' limit 1' into i, j, k; + raise notice '% % %', i, j, k; + execute 'select 1,2' into _v; + return _v; +end; $$ language plpgsql; +select execute_into_test('eifoo'); +NOTICE: 10 1 +NOTICE: 10 15 +NOTICE: 10 15 20 + execute_into_test +------------------- + (1,2) +(1 row) + +drop table eifoo cascade; +drop type eitype cascade; diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql index 7ea7c8c6e0..314f69915f 100644 --- a/src/test/regress/sql/plpgsql.sql +++ b/src/test/regress/sql/plpgsql.sql @@ -2018,3 +2018,35 @@ select missing_return_expr(); drop function void_return_expr(); drop function missing_return_expr(); + +-- +-- EXECUTE ... INTO test +-- + +create table eifoo (i integer, y integer); +create type eitype as (i integer, y integer); + +create or replace function execute_into_test(varchar) returns record as $$ +declare + _r record; + _rt eifoo%rowtype; + _v eitype; + i int; + j int; + k int; +begin + execute 'insert into '||$1||' values(10,15)'; + execute 'select (row).* from (select row(10,1)::eifoo) s' into _r; + raise notice '% %', _r.i, _r.y; + execute 'select * from '||$1||' limit 1' into _rt; + raise notice '% %', _rt.i, _rt.y; + execute 'select *, 20 from '||$1||' limit 1' into i, j, k; + raise notice '% % %', i, j, k; + execute 'select 1,2' into _v; + return _v; +end; $$ language plpgsql; + +select execute_into_test('eifoo'); + +drop table eifoo cascade; +drop type eitype cascade;