foreign-key — Define a foreign-key.
<foreign-key foreignTable="foreignTableName"> <column-ref local="localColumnName" foreign="foreignColumnName" /> ... </foreign-key>
This element define a foreign key used for the table.
At least a column reference should be made to a
column previously defined in the table and in another
table. The column reference attribute local
stands for the local column that is foreign key, and the
attribute foreign stands for the foreign
column that is primary key in the foreign table.
The foreign-table attribute define the name
of the referenced foreign table.
A reference to another column, the
local attribute must match a
column name in the same table. The foreign
attribute must match a foreign table column name.
Multiple column-ref elements can be
inserted inside a foreign-key element.
Example 13. Foreign Key example
<project name="testProject"> ... <metadata> <table name="Suppliers"> <column name="supplier_id" data-type="integer"> ... </column> ... <primary-key> <column-ref column="supplier_id" /> </primary-key> </table> <table name="Supplier_Addresses"> <column name="supplier_address_id" data-type="integer"> </column> ... <column name="supplier_id" data-type="integer"> </column> ... <primary-key> <column-ref column="supplier_address_id" /> </primary-key> ... <foreign-key foreign-table="Suppliers"> <column-ref local="supplier_id" foreign="supplier_id" /> </foreign-key> </table> </metadata> ... </project>