update

diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 649ba1f017929672f2e8571ceed6ff73cb3eda7c..80d71c5882c989269dc22daea9cabdf7bb27f6ff 100644 (file)
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1,5 +1,5 @@
 
 
@@ -957,11 +957,13 @@ ERROR: Cannot insert a duplicate key into a unique index.
        MATCH matchtype
        
         
-         The type of comparison to do between the table data. There are
-         three types of matching, MATCH FULL, MATCH PARTIAL, and the
-         unspecified match type used if no match type is specified.
-         MATCH PARTIAL is not
-         currently supported.
+         There are three match types: MATCH FULL, MATCH PARTIAL, and a
+         default match type if none is specified. MATCH FULL will not
+         allow one column of a multi-column foreign key to be NULL
+         unless all foreign key columns are NULL. The default MATCH type
+         allows a single foreign key column to be NULL while other parts
+         of the foreign key are not NULL. MATCH PARTIAL is not currently
+         supported.
         
        
       
@@ -1174,7 +1176,7 @@ ERROR:  name referential integrity
     
     
      Currently Postgres only supports MATCH
-     FULL and an unspecified match type. In addition, the referenced
+     FULL and a default match type. In addition, the referenced
      columns are supposed to be the columns of a UNIQUE constraint in
      the referenced table, however Postgres
      does not enforce this.
@@ -1503,10 +1505,13 @@ FOREIGN KEY ( column [, ...] ) REFE
        MATCH matchtype
        
         
-         The type of comparison to do between the table data. There are
-         three types of matching, MATCH FULL, MATCH PARTIAL, and the
-         unspecified match type used if no match type is specified.
-         MATCH PARTIAL is not currently supported.
+         There are three match types: MATCH FULL, MATCH PARTIAL, and a
+         default match type if none is specified. MATCH FULL will not
+         allow one column of a multi-column foreign key to be NULL
+         unless all foreign key columns are NULL. The default MATCH type
+         allows a single foreign key column to be NULL while other parts
+         of the foreign key are not NULL. MATCH PARTIAL is not currently
+         supported.