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Diffstat (limited to 'doc/src/sgml/plpgsql.sgml')
| -rw-r--r-- | doc/src/sgml/plpgsql.sgml | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index ac5b2b4cfc..fb2fe735a6 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.97 2006/06/16 23:29:26 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.98 2006/08/12 20:05:54 tgl Exp $ --> <chapter id="plpgsql"> <title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title> @@ -2040,9 +2040,8 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>; The <replaceable>target</replaceable> is a record variable, row variable, or comma-separated list of scalar variables. The <replaceable>target</replaceable> is successively assigned each row - resulting from the <replaceable>query</replaceable> (which must be a - <command>SELECT</command> command) and the loop body is executed for each - row. Here is an example: + resulting from the <replaceable>query</replaceable> and the loop body is + executed for each row. Here is an example: <programlisting> CREATE FUNCTION cs_refresh_mviews() RETURNS integer AS $$ DECLARE @@ -2070,6 +2069,15 @@ $$ LANGUAGE plpgsql; </para> <para> + The <replaceable>query</replaceable> used in this type of <literal>FOR</> + statement can be any query that returns rows to the caller: + <command>SELECT</> (without <literal>INTO</>) is the most common case, + but you can also use <command>INSERT</>, <command>UPDATE</>, or + <command>DELETE</> with a <literal>RETURNING</> clause. Some utility + commands such as <command>EXPLAIN</> will work too. + </para> + + <para> The <literal>FOR-IN-EXECUTE</> statement is another way to iterate over rows: <synopsis> @@ -2078,12 +2086,11 @@ FOR <replaceable>target</replaceable> IN EXECUTE <replaceable>text_expression</r <replaceable>statements</replaceable> END LOOP <optional> <replaceable>label</replaceable> </optional>; </synopsis> - This is like the previous form, except that the source - <command>SELECT</command> statement is specified as a string - expression, which is evaluated and replanned on each entry to - the <literal>FOR</> loop. This allows the programmer to choose the speed of - a preplanned query or the flexibility of a dynamic query, just - as with a plain <command>EXECUTE</command> statement. + This is like the previous form, except that the source query + is specified as a string expression, which is evaluated and replanned + on each entry to the <literal>FOR</> loop. This allows the programmer to + choose the speed of a preplanned query or the flexibility of a dynamic + query, just as with a plain <command>EXECUTE</command> statement. </para> <note> |