rafal@xxxxxxxxxxxxxxxxxx writes: >> 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. > I must admit, the standard is not very easy reading for me; what exactly > does the standarad mean by "<unique column list>": > 1. is that a requirement for mathematical properties of that list, or The point is it says "shall be equal to", not "shall be a superset of". regards, tom lane
