Editorialization of some text discussing 'IS NULL' vs. '= NULL'.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6c3856d26f76caa203deeafa0ce30cf507ba8269..a26424372a0aededf57810105dc4b45dd7845ee9 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,5 +1,5 @@
 
 
@@ -301,20 +301,22 @@ PostgreSQL documentation
     expression = NULL
     because NULL is not equal to
     NULL.  (The null value represents an unknown value,
-    and it is not known whether two unknown values are equal.)
+    and it is not known whether two unknown values are equal.) This
+    behavior conforms to the SQL standard.
    
 
    
-    Some applications may (incorrectly) require that
+    Some applications may expect that
     expression = NULL
     returns true if expression evaluates to
-    the null value.  To support these applications, the run-time option
-    transform_null_equals can be turned on (e.g.,
-    SET transform_null_equals TO ON;).
-    PostgreSQL will then convert
-    x = NULL clauses to
-    x IS NULL.  This was 
-    the default behavior in releases 6.5 through 7.1.
+    the null value.  It is highly recommended that these applications
+    be modified to comply with the SQL standard. However, if that
+    cannot be done the transform_null_equals
+    configuration variable is available. If it is enabled,
+    PostgreSQL will convert x =
+    NULL clauses to x IS NULL.  This was
+    the default behavior in PostgreSQL
+    releases 6.5 through 7.1.