[Zope] ZSQL batching with dtml-in

Tino Wildenhain tino at wildenhain.de
Thu Dec 8 17:05:43 EST 2005


Am Donnerstag, den 08.12.2005, 13:46 -0800 schrieb Ed Colmar:
> Do ZSQL methods communicate with the dtml-in call and understand the 
> "size" attribute?

Not really.

> for example, in this dtml-in statement:
> <dtml-in SQL_get_large_list size=20 start=query_start>
> </dtml-in>
> 
> Will the database be queried for all results, and only have 20 
> displayed, or will the database just return the 20 that are needed?

Well, this depends (in theory at least :) on the database
adaptor. It could just fetch the results up to 20 but
usually it will just fetch all and cut the batch
out of it. This isnt so bad as it seems because
you can have the ZSQL Method cache the result so
the database isnt asked any time.

You dont need DTML for batching. There is a batch
module you can use in python scripts as well
(and with ZPT)

HTH
Tino



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