On 15-09-2010 20:12, Nicolas Williams wrote: > On Wed, Sep 15, 2010 at 08:05:26PM +0200, Stef Mientki wrote: >> On 15-09-2010 11:36, Benoit Mortgat wrote: >>> Are you sure that after altering your tables adding columns, natural >>> join still only joins on vlid? >>> >> no, very stupid of me !! >> I added a column to each of the tables, with the same name, they >> should have the same value, but due to another programming error, the >> values were different. again, thank all very much !! >> >> That brings another issue to my mind, which I still don't understand: >> "why can we so easily manipulate complex pages of text, by adding / >> deleting / copying / pasting etc, and is manipulating of a few tables >> in a database so difficult?" > You shouldn't select * and you shouldn't natural joins precisely to > avoid these sorts of surprises. Select * is handy for manual queries > from a shell; ditto natural joins. > > Of course, you can always change your schema in such a way as to break > existing statements. But the point here is to write statements such > that they will be stable in the face of a schema that evolves in a > backwards compatible way. When you have to radically change your schema > you know you have to update your code; when you're merely adding columns > that don't contribute to primary keys then you shouldn't have to go > change any statements other than the ones where you specifically need > the new columns. SQL shortcuts like '*' and natural join are just not > compatible with such a schema evolution model. > thanks Nico, I think these are very valuable tips.
cheers, Stef > Nico _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
