[python-sybase] problems with executing dynamically created queries.

[Dave Cole]

Erik Thiele wrote:
> On Fri, 23 Jul 2004 14:19:32 +1000
> Dave Cole <djc@object-craft.com.au> wrote:
> 
> 
>>Erik Thiele wrote:
>>
>>
>>>and... why is there several styles in DB API 2.0? i mean the
>>>Sybase.paramstyle thing. i thought DB API was there for portability,
>>>and then i find out that different modules have different ways to
>>>create sql queries. so there is absolute zero portability. why?
>>
>>You will have to ask the database vendors that one.
> 
> 
> ah! so it's a problem with the database? i thought that this parameter
> substitution thing was an issue of the DB API and every python database
> driver programmer just decides which one to use. so that's not true!
> actually there should be a wrapper function on top of DB API that can
> transform one single paramstyle into all the others. or is there a
> technical reason why that's not possible? anyway once you maybe answer
> this question i will make a suggestion to python DB guys to add this to
> the FAQ. i tried to figure out why this is so for just too long time.
> also that FAQ entry must point out why there is no wrapper, or where it
> is :)

I am not sure that it is that simple for all databases.  If at all 
possible it is a good idea to pass binary parameters to the server and 
let the binding of parameters to the SQL occur at the server. 
Unfortunately each database vendor has decided upon different parameter 
placeholders.  Some databases do not support parameter passing so the 
client side must format the arguments into the SQL query sent to the server.

It might be a good idea if some very clever person developed a 
bullet-proof SQL query formatter that worked for all SQL variants.  Then 
the DB-API would just need to include formatters for native database 
types that could yield strings to be used by the formatter.  Who knows - 
this might have already been done.

- Dave

-- 
http://www.object-craft.com.au