database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-04-24 10:47:04 +03:00
Code

Add support for an optional INTO clause to PL/PgSQL's EXECUTE command.

Browse Source 
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.
This commit is contained in:
Neil Conway 2005-06-07 02:47:23 +00:00
parent 0f011f6daa
commit c59887f916
6 changed files with 169 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
doc/src/sgml/plpgsql.sgml
View File

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.69 2005/05/26 04:08:31 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.70 2005/06/07 02:47:15 neilc Exp $
-->
<chapter id="plpgsql">
@ -1251,13 +1251,14 @@ NULL;
<command>EXECUTE</command> statement is provided:
<synopsis>
EXECUTE <replaceable class="command">command-string</replaceable>;
EXECUTE <replaceable class="command">command-string</replaceable> [ INTO <replaceable>target</replaceable> ];
</synopsis>
where <replaceable>command-string</replaceable> is an expression
yielding a string (of type
<type>text</type>) containing the command
to be executed. This string is fed literally to the SQL engine.
yielding a string (of type <type>text</type>) containing the
command to be executed and <replaceable>target</replaceable> is a
record variable, row variable, or a comma-separated list of
simple variables and record/row fields.
</para>
<para>
@ -1276,16 +1277,22 @@ EXECUTE <replaceable class="command">command-string</replaceable>;
</para>
<para>
The results from <command>SELECT</command> commands are discarded
by <command>EXECUTE</command>, and <command>SELECT INTO</command>
is not currently supported within <command>EXECUTE</command>.
So there is no way to extract a result from a dynamically-created
<command>SELECT</command> using the plain <command>EXECUTE</command>
command. There are two other ways to do it, however: one is to use the
<command>FOR-IN-EXECUTE</>
loop form described in <xref linkend="plpgsql-records-iterating">,
and the other is to use a cursor with <command>OPEN-FOR-EXECUTE</>, as
described in <xref linkend="plpgsql-cursor-opening">.
The <literal>INTO</literal> clause specifies where the results of
a <command>SELECT</command> command should be assigned. If a row
or variable list is provided, it must exactly match the structure
of the results produced by the <command>SELECT</command> (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 <literal>INTO</literal>
variable. If no rows are returned, NULL is assigned to the
<literal>INTO</literal> variable. If no <literal>INTO</literal>
clause is specified, the results of a <command>SELECT</command>
command are discarded.
</para>
<para>
<command>SELECT INTO</command> is not currently supported within
<command>EXECUTE</command>.
</para>
<para>
@ -1364,7 +1371,7 @@ EXECUTE 'UPDATE tbl SET '
command, which has the form:
<synopsis>
GET DIAGNOSTICS <replaceable>variable</replaceable> = <replaceable>item</replaceable> <optional> , ... </optional> ;
GET DIAGNOSTICS <replaceable>variable</replaceable> = <replaceable>item</replaceable> <optional> , ... </optional>;
</synopsis>
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:
<synopsis>
<replaceable>name</replaceable> CURSOR <optional> ( <replaceable>arguments</replaceable> ) </optional> FOR <replaceable>query</replaceable> ;
<replaceable>name</replaceable> CURSOR <optional> ( <replaceable>arguments</replaceable> ) </optional> FOR <replaceable>query</replaceable>;
</synopsis>
(<literal>FOR</> may be replaced by <literal>IS</> for
<productname>Oracle</productname> compatibility.)
@ -2218,7 +2225,7 @@ DECLARE
<title><command>OPEN FOR</command> <replaceable>query</replaceable></title>
<synopsis>
OPEN <replaceable>unbound_cursor</replaceable> FOR <replaceable>query</replaceable> ;
OPEN <replaceable>unbound_cursor</replaceable> FOR <replaceable>query</replaceable>;
</synopsis>
<para>
@ -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 &lt;record&gt; construct.

49
src/pl/plpgsql/src/gram.y
View File

@ -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;

29
src/pl/plpgsql/src/pl_exec.c
View File

@ -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:

4
src/pl/plpgsql/src/plpgsql.h
View File

@ -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;

35
src/test/regress/expected/plpgsql.out
View File

@ -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;

32
src/test/regress/sql/plpgsql.sql
View File

@ -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;