Add contraint exclusion section to contraint docs.

Takahiro Itagaki

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 01f9acfd23e7e0ac448e1ccdb4a9fd29d0786478..334ad51082c567588c3b3325c594edfed71e624d 100644 (file)
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  Data Definition
@@ -845,6 +845,36 @@ CREATE TABLE order_items (
     .
    
   
+
+  
+   Exclusion constraints
+
+   
+    exclusion constraint
+   
+
+   
+    constraint
+    exclusion
+   
+
+   
+    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:
+
+CREATE TABLE circles (
+    c circle,
+    EXCLUDE USING gist (c WITH &&)
+);
+
+   
+
+   
+    See also CREATE
+    TABLE ... CONSTRAINT ... EXCLUDE for details.
+   
+