On 5 Dec 2002 at 9:51, Stephan Szabo wrote: > On Thu, 5 Dec 2002, Dan Langille wrote: > > > On 5 Dec 2002 at 9:31, Stephan Szabo wrote: > > > > > When we talk about ALTER TABLE ADD FOREIGN KEY we're being imprecise, so > > > I think that might be why we're talking past each other here. > > > > > > Technically the syntax in question is: > > > ALTER TABLE <table> ADD <table constraint definition> > > > where CONSTRAINT <name> is an optional leading clause in a table > > > constraint definition. ADD FOREIGN KEY is a shorthand for a foreign key > > > constraint (technically unnamed). > > > > Understood. > > > > What about allowing a named foreign key? I haven't checked the RFCs > > Here's a part of what SQL92 (draft) has to say about table constraint > definitions: > > <table constraint definition> ::= > [ <constraint name definition> ] > <table constraint> [ <constraint attributes> ] > > <table constraint> ::= > <unique constraint definition> > | <referential constraint definition> > | <check constraint definition> > > > <constraint name definition> ::= CONSTRAINT <constraint name> > > <referential constraint definition> ::= > FOREIGN KEY <left paren> <referencing columns> <right paren> > <references specification> > > 11.6 Syntax Rules > > 2) If <constraint name definition> is not specified, then a <con- > straint name definition> that contains an implementation- > dependent <constraint name> is implicit. The assigned <con- > straint name> shall obey the Syntax Rules of an explicit <con- > straint name>. > > In our case, the implementation dependent naming scheme is I believe > "$<n>" where <n> is the maximum one already there for that table +1 I > would guess.
Thanks. I guess I should rename my thread to 7.4 - TODO : allow constraint names when using the "ALTER TABLE <table> ADD FOREIGN KEY" syntax. -- Dan Langille : http://www.langille.org/ ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
