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More minor updates and copy-editing.

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This commit is contained in:
Tom Lane
2005-01-04 03:58:16 +00:00
parent 248d92ddf4
commit cc093bc3ad
10 changed files with 322 additions and 274 deletions
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22
doc/src/sgml/ref/update.sgml
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@@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.30 2004/08/08 01:48:31 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.31 2005/01/04 03:58:16 tgl Exp $
PostgreSQL documentation
-->
@@ -150,6 +150,26 @@ UPDATE <replaceable class="parameter">count</replaceable>
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
When joining the target table to other tables using a <replaceable
class="PARAMETER">fromlist</replaceable>, be careful that the join
produces at most one output row for each row to be modified. In
other words, a target row mustn't join to more than one row from
the other table(s). If it does, then only one of the join rows
will be used to update the target row, but which one will be used
is not readily predictable.
</para>
<para>
Because of this indeterminancy, referencing other tables only within
sub-selects is safer, though often harder to read and slower than
using a join.
</para>
</refsect1>
<refsect1>
<title>Examples</title>