diff options
Diffstat (limited to 'doc/src/sgml/ref')
| -rw-r--r-- | doc/src/sgml/ref/create_index.sgml | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml index 49352accae0..1966cb9daeb 100644 --- a/doc/src/sgml/ref/create_index.sgml +++ b/doc/src/sgml/ref/create_index.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.71 2009/03/24 20:17:08 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_index.sgml,v 1.72 2009/12/23 17:41:43 tgl Exp $ PostgreSQL documentation --> @@ -21,7 +21,7 @@ PostgreSQL documentation <refsynopsisdiv> <synopsis> -CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</replaceable> ON <replaceable class="parameter">table</replaceable> [ USING <replaceable class="parameter">method</replaceable> ] +CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table</replaceable> [ USING <replaceable class="parameter">method</replaceable> ] ( { <replaceable class="parameter">column</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] ) [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ] [ TABLESPACE <replaceable class="parameter">tablespace</replaceable> ] @@ -33,8 +33,8 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re <title>Description</title> <para> - <command>CREATE INDEX</command> constructs an index named <replaceable - class="parameter">name</replaceable> on the specified table. + <command>CREATE INDEX</command> constructs an index + on the specified column(s) of the specified table. Indexes are primarily used to enhance database performance (though inappropriate use can result in slower performance). </para> @@ -132,7 +132,9 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] <replaceable class="parameter">name</re <para> The name of the index to be created. No schema name can be included here; the index is always created in the same schema as its parent - table. + table. If the name is omitted, <productname>PostgreSQL</> chooses a + suitable name based on the parent table's name and the indexed column + name(s). </para> </listitem> </varlistentry> @@ -514,8 +516,10 @@ CREATE UNIQUE INDEX title_idx ON films (title); To create an index on the expression <literal>lower(title)</>, allowing efficient case-insensitive searches: <programlisting> -CREATE INDEX lower_title_idx ON films ((lower(title))); +CREATE INDEX ON films ((lower(title))); </programlisting> + (In this example we have chosen to omit the index name, so the system + will choose a name, typically <literal>films_lower_idx</>.) </para> <para> @@ -544,7 +548,7 @@ CREATE INDEX gin_idx ON documents_table (locations) WITH (fastupdate = off); <literal>films</> and have the index reside in the tablespace <literal>indexspace</>: <programlisting> -CREATE INDEX code_idx ON films(code) TABLESPACE indexspace; +CREATE INDEX code_idx ON films (code) TABLESPACE indexspace; </programlisting> </para> |