diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/plpgsql.sgml | 45 |
1 files changed, 26 insertions, 19 deletions
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 7d2b37e41d7..d96c123e21c 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -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 <record> construct. |