Marc-Andre, > The standard SQL notation for value lists in SQL is > > x in (value1, value2, ...) > > so this should work pretty much with every SQL database.
yes. If I know the number of values beforhand, even parameters work: x in (:value1, :value2, :value3) (for being ":" the parametersubstitution of choice for the database > If you have numbers as sequence elements, the Python tuple > representation works just fine. I am going to test this, if something like "x in (:mypytu)", dict(mypytu=(1,2,3))" works ... thanks for the hint! I stopped testing when I failed with set() and list() :) >For strings, things are harder, but then I wouldn't recommend using IN predicates with >strings anyway - it's better to map the strings to integers via an extra table (if possible). Why is it better? If I get a set of strings from the application, I have to find the fitting integers from the extra table. That again is one in-call; or number-of-strings calls, which for performance reasons esp,. on WAN is not nice :( > Note that you can also write: > (x == value1) or (x == value2) ... Thanks for the reminder! > That way you avoid having to deal with escaping - you still > have to construct the SQL depending on the number of values > you have. I think that is a good trade. "Constructing SQL" is a easier to test then "correctly escaping every *** that somebody puts in" :) > several databases have functions > for doing substring-search. All you'd have to do is join all > the members using e.g. ',' (provided none of the members > has this character) and the do something like: WOW! Thats a nice trick, thinking out of the box ... thanks! > BTW, sequences in DB-talk are objects which you can use as > auto-increment integer source, e.g. for creating ids of > new rows. Yes. Maybe that makes it hard to google up a solution for my challenge :) Thanks for your great hints, best wishes, Harald (cu @ EP2007 ? ) -- GHUM Harald Massa persuadere et programmare Harald Armin Massa Reinsburgstraße 202b 70197 Stuttgart 0173/9409607 - Python: the only language with more web frameworks than keywords. _______________________________________________ DB-SIG maillist - DB-SIG@python.org http://mail.python.org/mailman/listinfo/db-sig
