Re: Foreign Keys as first class citizens at design time?

[Peter Brawley]

> Then in the respective SQL syntax a symantic [sic] reference
> may then be made whether or not to follow such links

> SELECT directory-name FROM system WITH-IMPLICIT-JOIN WHERE-PK-IS-NOT-LINKED

SQL isn't a complete computer language, it's quite literal in some respects, can't do such refs. You'd need to implement the logic of such refs in an app language layer.

> you would need a separate table for each level in your directory

Other SQL dialects have tree traversal syntax, MySQL hasn't, so in MySQL you need procedural code to traverse hierarchies of undetermined depth.