doc: Add more compatibility information for triggers

Louis-Claude Canon and Josh Kupershmidt

diff --git a/doc/src/sgml/ref/create_trigger.sgml b/doc/src/sgml/ref/create_trigger.sgml
index 0f87b1fc96d3971b070b4fbda8ee1c752614bb88..d9817e4a9e187aabbe569060ea93f7d5527293b7 100644 (file)
--- a/doc/src/sgml/ref/create_trigger.sgml
+++ b/doc/src/sgml/ref/create_trigger.sgml
@@ -484,7 +484,8 @@ CREATE TRIGGER view_insert
   
    The CREATE TRIGGER statement in
    PostgreSQL implements a subset of the
-   SQL standard. The following functionality is currently missing:
+   SQL standard. The following functionalities are currently
+   missing:
 
    
     
@@ -500,6 +501,16 @@ CREATE TRIGGER view_insert
      
     
 
+    
+     
+      PostgreSQL does not allow the old and new
+      tables to be referenced in statement-level triggers, i.e., the tables
+      that contain all the old and/or new rows, which are referred to by the
+      OLD TABLE and NEW TABLE clauses in
+      the SQL standard.
+     
+    
+
     
      PostgreSQL only allows the execution
       of a user-defined function for the triggered action.  The standard