Add warning about DOMAINs.

David Fetter

diff --git a/doc/src/sgml/ref/create_domain.sgml b/doc/src/sgml/ref/create_domain.sgml
index bda71b12116191cde55fdc5832511eec8f2cc0f6..94a73d12525736cb2ea1fd2d7521ecdfb0ded291 100644 (file)
--- a/doc/src/sgml/ref/create_domain.sgml
+++ b/doc/src/sgml/ref/create_domain.sgml
@@ -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>