mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Document that NOT NULL domain constraints are not always honored.

Browse Source
This commit is contained in:
Bruce Momjian 2010-05-29 19:06:16 +00:00
parent 23e9fe0391
commit d800b036d2
1 changed files with 7 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
doc/src/sgml/ref/create_domain.sgml
View File

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.34 2010/04/03 07:22:58 petere Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_domain.sgml,v 1.35 2010/05/29 19:06:16 momjian Exp $
PostgreSQL documentation
-->
@ -121,7 +121,12 @@ CREATE DOMAIN <replaceable class="parameter">name</replaceable> [ AS ] <replacea
<term><literal>NOT NULL</></term>
<listitem>
<para>
Values of this domain are not allowed to be null.
Values of this domain are normally prevented from being null.
However, it is still possible for a domain with this constraint
to take a null value if it is assigned a matching domain type
that has become null, e.g. via a LEFT OUTER JOIN, or
<command>INSERT INTO tab (domcol) VALUES ((SELECT domcol FROM
tab WHERE false))</command>.
</para>
</listitem>
</varlistentry>