> 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". So its the "meaning nr.2". The "syntax glue" not the actual math of sets. This is strange, I must say. But no further questions when this is a "syntax" requirement. Thenx, -R
