Reword exclusion constriants to mention that the operator can return

false or null, per Tom.
This commit is contained in:
Bruce Momjian 2010-04-06 02:18:04 +00:00
parent f1926c93c8
commit 08c1d4e560

View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/ddl.sgml,v 1.92 2010/04/03 07:22:53 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/ddl.sgml,v 1.93 2010/04/06 02:18:04 momjian Exp $ -->
<chapter id="ddl">
<title>Data Definition</title>
@ -861,7 +861,8 @@ CREATE TABLE order_items (
<para>
Exclusion constraints ensure that if any two rows are compared on
the specified columns or expressions using the specified operators,
at least one of these operator comparisons will be false. The syntax is:
at least one of these operator comparisons will return false or null.
The syntax is:
<programlisting>
CREATE TABLE circles (
c circle,