Gregory Stark <[EMAIL PROTECTED]> writes: > I'm not sure if there's a fundamental reason why there has to be an index that > exactly matches the foreign key or not -- offhand I can't think of one.
The reason why is that the SQL spec says so: a) If the <referenced table and columns> specifies a <reference column list>, then the set of <column name>s contained in that <reference column list> shall be equal to the set of <column name>s contained in the <unique column list> of a unique constraint of the referenced table. Let referenced columns be the column or columns identified by that <reference column list> and let referenced column be one such column. Each referenced column shall identify a column of the referenced table and the same column shall not be identified more than once. I'm not entirely sure, but I think the restrictive definition might be necessary with some of the more complex options for foreign keys, such as MATCH PARTIAL. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general