diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/indices.sgml | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml index 6fcb6968ffc..3de05419226 100644 --- a/doc/src/sgml/indices.sgml +++ b/doc/src/sgml/indices.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.72 2007/11/13 23:36:26 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.73 2008/05/27 00:13:08 tgl Exp $ --> <chapter id="indexes"> <title id="indexes-title">Indexes</title> @@ -906,11 +906,10 @@ CREATE INDEX <replaceable>name</replaceable> ON <replaceable>table</replaceable> <listitem> <para> The operator classes <literal>text_pattern_ops</literal>, - <literal>varchar_pattern_ops</literal>, - <literal>bpchar_pattern_ops</literal>, and - <literal>name_pattern_ops</literal> support B-tree indexes on - the types <type>text</type>, <type>varchar</type>, - <type>char</type>, and <type>name</type>, respectively. The + <literal>varchar_pattern_ops</literal>, and + <literal>bpchar_pattern_ops</literal> support B-tree indexes on + the types <type>text</type>, <type>varchar</type>, and + <type>char</type> respectively. The difference from the default operator classes is that the values are compared strictly character by character rather than according to the locale-specific collation rules. This makes @@ -923,10 +922,12 @@ CREATE INDEX <replaceable>name</replaceable> ON <replaceable>table</replaceable> CREATE INDEX test_index ON test_table (col varchar_pattern_ops); </programlisting> Note that you should also create an index with the default operator - class if you want queries involving ordinary comparisons to use an - index. Such queries cannot use the + class if you want queries involving ordinary <literal><</>, + <literal><=</>, <literal>></>, or <literal>>=</> comparisons + to use an index. Such queries cannot use the <literal><replaceable>xxx</replaceable>_pattern_ops</literal> - operator classes. It is allowed to create multiple + operator classes. (Ordinary equality comparisons can use these + operator classes, however.) It is allowed to create multiple indexes on the same column with different operator classes. If you do use the C locale, you do not need the <literal><replaceable>xxx</replaceable>_pattern_ops</literal> |