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Modify UPDATE/DELETE WHERE CURRENT OF to use the FOR UPDATE infrastructure to

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locate the target row, if the cursor was declared with FOR UPDATE or FOR
SHARE.  This approach is more flexible and reliable than digging through the
plan tree; for instance it can cope with join cursors.  But we still provide
the old code for use with non-FOR-UPDATE cursors.  Per gripe from Robert Haas.
This commit is contained in:
Tom Lane
2008-11-16 17:34:28 +00:00
parent 30f272a79b
commit 18004101ac
9 changed files with 246 additions and 70 deletions
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11
doc/src/sgml/ref/update.sgml
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@@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.47 2008/11/14 10:22:47 petere Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.48 2008/11/16 17:34:28 tgl Exp $
PostgreSQL documentation
-->
@@ -167,10 +167,13 @@ UPDATE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ [ AS ] <rep
<para>
The name of the cursor to use in a <literal>WHERE CURRENT OF</>
condition. The row to be updated is the one most recently fetched
from this cursor. The cursor must be a simple (non-join, non-aggregate)
from this cursor. The cursor must be a non-grouping
query on the <command>UPDATE</>'s target table.
Note that <literal>WHERE CURRENT OF</> cannot be
specified together with a Boolean condition.
specified together with a Boolean condition. See
<xref linkend="sql-declare" endterm="sql-declare-title">
for more information about using cursors with
<literal>WHERE CURRENT OF</>.
</para>
</listitem>
</varlistentry>
@@ -331,7 +334,7 @@ COMMIT;
<literal>c_films</> is currently positioned:
<programlisting>
UPDATE films SET kind = 'Dramatic' WHERE CURRENT OF c_films;
</programlisting>
</programlisting>
</para>
</refsect1>