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1 | 1 | <!-- |
2 | | -$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.23 2000/04/1421:44:21 momjian Exp $ |
| 2 | +$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v 1.24 2000/04/1422:13:24 momjian Exp $ |
3 | 3 | Postgres documentation |
4 | 4 | --> |
5 | 5 |
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@@ -957,11 +957,13 @@ ERROR: Cannot insert a duplicate key into a unique index. |
957 | 957 | <term>MATCH <replaceable class="parameter">matchtype</replaceable></term> |
958 | 958 | <listitem> |
959 | 959 | <para> |
960 | | - The type of comparison to do between the table data. There are |
961 | | - three types of matching, MATCH FULL, MATCH PARTIAL, and the |
962 | | - unspecified match type used if no match type is specified. |
963 | | - MATCH PARTIAL is not |
964 | | - currently supported. |
| 960 | + There are three match types: MATCH FULL, MATCH PARTIAL, and a |
| 961 | + default match type if none is specified. MATCH FULL will not |
| 962 | + allow one column of a multi-column foreign key to be NULL |
| 963 | + unless all foreign key columns are NULL. The default MATCH type |
| 964 | + allows a single foreign key column to be NULL while other parts |
| 965 | + of the foreign key are not NULL. MATCH PARTIAL is not currently |
| 966 | + supported. |
965 | 967 | </para> |
966 | 968 | </listitem> |
967 | 969 | </varlistentry> |
@@ -1174,7 +1176,7 @@ ERROR: <replaceable class="parameter">name</replaceable> referential integrity |
1174 | 1176 | </title> |
1175 | 1177 | <para> |
1176 | 1178 | Currently <productname>Postgres</productname> only supports MATCH |
1177 | | - FULL andan unspecified match type. In addition, the referenced |
| 1179 | + FULL anda default match type. In addition, the referenced |
1178 | 1180 | columns are supposed to be the columns of a UNIQUE constraint in |
1179 | 1181 | the referenced table, however <productname>Postgres</productname> |
1180 | 1182 | does not enforce this. |
@@ -1503,10 +1505,13 @@ FOREIGN KEY ( <replaceable class="parameter">column</replaceable> [, ...] ) REFE |
1503 | 1505 | <term>MATCH <replaceable class="parameter">matchtype</replaceable></term> |
1504 | 1506 | <listitem> |
1505 | 1507 | <para> |
1506 | | - The type of comparison to do between the table data. There are |
1507 | | - three types of matching, MATCH FULL, MATCH PARTIAL, and the |
1508 | | - unspecified match type used if no match type is specified. |
1509 | | - MATCH PARTIAL is not currently supported. |
| 1508 | + There are three match types: MATCH FULL, MATCH PARTIAL, and a |
| 1509 | + default match type if none is specified. MATCH FULL will not |
| 1510 | + allow one column of a multi-column foreign key to be NULL |
| 1511 | + unless all foreign key columns are NULL. The default MATCH type |
| 1512 | + allows a single foreign key column to be NULL while other parts |
| 1513 | + of the foreign key are not NULL. MATCH PARTIAL is not currently |
| 1514 | + supported. |
1510 | 1515 | </para> |
1511 | 1516 | </listitem> |
1512 | 1517 | </varlistentry> |
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