[BioSQL-l] columns in compound keys

[Hilmar Lapp]

I changed the version columns in dbxref and bioentry to be NOT NULL and 
added a comment stating what to put there if you don't have a version 
and how to interpret a version of 0 (zero).

Related to this, what are peoples' feelings about adding NOT NULL to 
the various 'rank' columns that participate in a compound unique key 
(with the same default convention if there is no sensible rank)?

I don't have a strong opinion about that since in all those cases I 
made sure I do assign a rank in the adaptor code before insert, because 
I ran into trouble without doing so, which means I got different 
behaviour between different RDBMSs (something that was fine on one 
threw a UK violation on another). So, for the same reasons I'd strongly 
recommend that adaptor developers define a version anyway, regardless 
of whether the schema leaves it optional. So, one might just as well 
demand it in the schema.

	-hilmar
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Hilmar Lapp                            email: lapp at gnf.org
GNF, San Diego, Ca. 92121              phone: +1-858-812-1757
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