diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml index 649ba1f017929672f2e8571ceed6ff73cb3eda7c..80d71c5882c989269dc22daea9cabdf7bb27f6ff 100644 --- a/doc/src/sgml/ref/create_table.sgml +++ b/doc/src/sgml/ref/create_table.sgml @@ -1,5 +1,5 @@ <!-- -$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.23 2000/04/14 21:44:21 momjian Exp $ +$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.24 2000/04/14 22:13:24 momjian Exp $ Postgres documentation --> @@ -957,11 +957,13 @@ ERROR: Cannot insert a duplicate key into a unique index. <term>MATCH <replaceable class="parameter">matchtype</replaceable></term> <listitem> <para> - 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. </para> </listitem> </varlistentry> @@ -1174,7 +1176,7 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity </title> <para> Currently <productname>Postgres</productname> 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 <productname>Postgres</productname> does not enforce this. @@ -1503,10 +1505,13 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE <term>MATCH <replaceable class="parameter">matchtype</replaceable></term> <listitem> <para> - 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. </para> </listitem> </varlistentry>