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Change array comparison rules to consider dimensionality information,

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not only the array contents, before claiming two arrays are equal.
Per recent discussion.
This commit is contained in:
Tom Lane
2005-11-19 19:44:55 +00:00
parent daea4d8eae
commit 659f681638
2 changed files with 47 additions and 10 deletions
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15
doc/src/sgml/func.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.294 2005/11/19 01:50:08 tgl Exp $
$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.295 2005/11/19 19:44:54 tgl Exp $
PostgreSQL documentation
-->
@ -7403,6 +7403,19 @@ SELECT NULLIF(value, '(none)') ...
</tgroup>
</table>
<para>
Array comparisons compare the array contents element-by-element,
using the default btree comparison function for the element data type.
In multidimensional arrays the elements are visited in row-major order
(last subscript varies most rapidly).
If the contents of two arrays are equal but the dimensionality is
different, the first difference in the dimensionality information
determines the sort order. (This is a change from versions of
<productname>PostgreSQL</> prior to 8.2: older versions would claim
that two arrays with the same contents were equal, even if the
number of dimensions or subscript ranges were different.)
</para>
<para>
See <xref linkend="arrays"> for more details about array operator
behavior.