diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 649ba1f0179..80d71c5882c 100644
--- 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.