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Add warning about DOMAINs.

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David Fetter
This commit is contained in:
Bruce Momjian 2005-09-22 23:56:46 +00:00
parent c79671bdbb
commit 0135cd88bd
1 changed files with 8 additions and 5 deletions

13
doc/src/sgml/ref/create_domain.sgml

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.22 2005/05/02 01:52:50 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.23 2005/09/22 23:56:46 momjian Exp $
PostgreSQL documentation
-->
@ -48,10 +48,13 @@ where <replaceable class="PARAMETER">constraint</replaceable> is:
</para>
<para>
Domains are useful for abstracting common fields between tables into
a single location for maintenance. For example, an email address column may be used
in several tables, all with the same properties. Define a domain and
use that rather than setting up each table's constraints individually.
Domains are useful for abstracting common fields between tables
into a single location for maintenance. For example, an email address
column may be used in several tables, all with the same properties.
Define a domain and use that rather than setting up each table's
constraints individually. <note>Keep in mind also that declaring a
function result value as a domain is pretty dangerous, because none of
the PLs enforce domain constraints on their results.</note>
</para>
</refsect1>