diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/select.sgml | 32 | ||||
| -rw-r--r-- | doc/src/sgml/ref/select_into.sgml | 4 | ||||
| -rw-r--r-- | doc/src/sgml/sql.sgml | 4 |
3 files changed, 24 insertions, 16 deletions
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml index f862d5f8737..b15aa361a0f 100644 --- a/doc/src/sgml/ref/select.sgml +++ b/doc/src/sgml/ref/select.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.90 2005/11/01 21:09:51 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.91 2006/04/30 18:30:38 tgl Exp $ PostgreSQL documentation --> @@ -30,7 +30,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac [ ORDER BY <replaceable class="parameter">expression</replaceable> [ ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] [, ...] ] [ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ] [ OFFSET <replaceable class="parameter">start</replaceable> ] - [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] ] + [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] [...] ] where <replaceable class="parameter">from_item</replaceable> can be one of: @@ -142,8 +142,8 @@ where <replaceable class="parameter">from_item</replaceable> can be one of: <listitem> <para> - If the <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal> - clause is specified, the + If <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal> + is specified, the <command>SELECT</command> statement locks the selected rows against concurrent updates. (See <xref linkend="sql-for-update-share" endterm="sql-for-update-share-title"> below.) @@ -853,18 +853,26 @@ FOR SHARE [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] </para> <para> - It is currently not allowed for a single <command>SELECT</command> - statement to include both <literal>FOR UPDATE</literal> and - <literal>FOR SHARE</literal>, nor can different parts of the statement use - both <literal>NOWAIT</> and normal waiting mode. - </para> - - <para> If specific tables are named in <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal>, then only rows coming from those tables are locked; any other tables used in the <command>SELECT</command> are simply read as - usual. + usual. A <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal> + clause without a table list affects all tables used in the command. + If <literal>FOR UPDATE</literal> or <literal>FOR SHARE</literal> is + applied to a view or sub-query, it affects all tables used in + the view or sub-query. + </para> + + <para> + Multiple <literal>FOR UPDATE</literal> and <literal>FOR SHARE</literal> + clauses can be written if it is necessary to specify different locking + behavior for different tables. If the same table is mentioned (or + implicitly affected) by both <literal>FOR UPDATE</literal> and + <literal>FOR SHARE</literal> clauses, then it is processed as + <literal>FOR UPDATE</literal>. Similarly, a table is processed + as <literal>NOWAIT</> if that is specified in any of the clauses + affecting it. </para> <para> diff --git a/doc/src/sgml/ref/select_into.sgml b/doc/src/sgml/ref/select_into.sgml index d9967197b87..283fd4f8b20 100644 --- a/doc/src/sgml/ref/select_into.sgml +++ b/doc/src/sgml/ref/select_into.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.36 2005/08/01 20:31:04 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/select_into.sgml,v 1.37 2006/04/30 18:30:38 tgl Exp $ PostgreSQL documentation --> @@ -31,7 +31,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac [ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ] [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ] [ OFFSET <replaceable class="PARAMETER">start</replaceable> ] - [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] ] + [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] [...] ] </synopsis> </refsynopsisdiv> diff --git a/doc/src/sgml/sql.sgml b/doc/src/sgml/sql.sgml index 86539ded117..b27400b4a45 100644 --- a/doc/src/sgml/sql.sgml +++ b/doc/src/sgml/sql.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/sql.sgml,v 1.39 2006/03/10 19:10:49 momjian Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/sql.sgml,v 1.40 2006/04/30 18:30:38 tgl Exp $ --> <chapter id="sql-intro"> <title>SQL</title> @@ -863,7 +863,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac [ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ] [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ] [ OFFSET <replaceable class="PARAMETER">start</replaceable> ] - [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] ] + [ FOR { UPDATE | SHARE } [ OF <replaceable class="parameter">table_name</replaceable> [, ...] ] [ NOWAIT ] [...] ] </synopsis> </para> |