database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-27 12:41:57 +03:00
Code Activity

Revert my patch of 2009-04-04 that removed contrib/intarray's definitions of

Browse Source 
the <@ and @> operators.  These are not in fact equivalent to the built-in
anyarray operators of the same names, because they have different behavior for
empty arrays, namely they don't think empty arrays are contained in anything.
That is mathematically wrong, no doubt, but until we can persuade GIN indexes
to implement the mathematical definition we should probably not change this.
Another reason for not changing it now is that we can't yet ensure the
opclasses will be updated correctly in a dump-and-reload upgrade.  Per
recent discussions.
This commit is contained in:
Tom Lane
2009-06-07 20:09:34 +00:00
parent 32ea236361
commit 156475a589
4 changed files with 50 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
doc/src/sgml/intarray.sgml
View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/intarray.sgml,v 1.7 2009/04/05 00:40:35 tgl Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/intarray.sgml,v 1.8 2009/06/07 20:09:34 tgl Exp $ -->
<sect1 id="intarray">
<title>intarray</title>
@ -134,12 +134,12 @@
<entry>overlap &mdash; <literal>true</> if arrays have at least one common element</entry>
</row>
<row>
<entry><literal>int[] @ int[]</literal></entry>
<entry><literal>int[] @&gt; int[]</literal></entry>
<entry><type>boolean</type></entry>
<entry>contains &mdash; <literal>true</> if left array contains right array</entry>
</row>
<row>
<entry><literal>int[] ~ int[]</literal></entry>
<entry><literal>int[] &lt;@ int[]</literal></entry>
<entry><type>boolean</type></entry>
<entry>contained &mdash; <literal>true</> if left array is contained in right array</entry>
</row>
@ -203,13 +203,22 @@
</table>
<para>
The containment operators <literal>@</> and <literal>~</> are functionally
equivalent to <productname>PostgreSQL</>'s built-in operators
<literal>@&gt;</> and <literal>&lt;@</>, respectively, except that
<literal>@</> and <literal>~</> work only on integer arrays. These
operator names are deprecated and will eventually be retired. (Notice that
these names are reversed from the convention formerly followed by the core
geometric datatypes!)
(Before PostgreSQL 8.2, the containment operators <literal>@&gt;</> and
<literal>&lt;@</> were respectively called <literal>@</> and <literal>~</>.
These names are still available, but are deprecated and will eventually be
retired. Notice that the old names are reversed from the convention
formerly followed by the core geometric datatypes!)
</para>
<para>
The containment operators <literal>@&gt;</> and <literal>&lt;@</> are
approximately equivalent to <productname>PostgreSQL</>'s built-in operators
of the same names, except that they work only on integer arrays while the
built-in operators work for any array type. An important difference is
that <filename>intarray</>'s operators do not consider an empty array to be
contained in anything else. This is consistent with the behavior of
GIN-indexed queries, but not with the usual mathematical definition of
containment.
</para>
<para>
@ -230,10 +239,8 @@
<para>
<filename>intarray</> provides index support for the
<literal>&amp;&amp;</>, <literal>@</>, <literal>~</>,
and <literal>@@</> operators, as well as regular array equality
and the built-in <literal>@&gt;</> and <literal>&lt;@</> operators
(when used on integer arrays).
<literal>&amp;&amp;</>, <literal>@&gt;</>, <literal>&lt;@</>,
and <literal>@@</> operators, as well as regular array equality.
</para>
<para>