[Zope] Re: dtml-Variablen in <dtml-in> loops?

[Tino Wildenhain]

Hi Philipp,

--On Sonntag, 27. Mai 2001 23:20 +0200 Philipp Robbel=20
<philipp.robbel@eml.villa-bosch.de> wrote:

> Hi Tino,
>
> the problem I see with your (I agree: much cleaner) code is that for
> each group you issue a SQL statement. So if I have 1000 groups you'll
> end up with 1000 SQL queries.

you will hardly show 1000 Records at once ;)

> In my (ugly :-) code you'd only have 2 sql queries:
> - the first one: sqlCount (see previous post)
> - the second (cached) one outside the iterations: DATA=3DsqlListProjects
> (large list with
>   1000*Projects rows).
>
> About the caching: I read that in Dieter's Zope Book:
> http://www.dieter.handshake.de/pyprojects/zope/book/chap3.html

Hm. So Dieter must be wrong since it is documented otherwise.
Even more, all database interactions are enclosed in a transaction
of the publishing process (if the database adaptor supports this -
and its supposed to do that)

>
> So my question remains: is there either DATA[1:a+b] (both a and b are
> dtml-Variables) possible or <dtml-in .. start=3Da+b..> (both a and b are
> dtml-Variables).

how about <dtml-in DATA start=3DGroupStart size=3DGroupCount orphan=3D0>
</dtml-in> ?

Another solution would be:

sqlProjectList:
SELECT GroupID,ProjectID,Project FROM Project ORDER BY GroupID,ProjectID

<dtml-call "REQUEST.set('marker',-1)">
<dtml-in sqlProjectList>
   <dtml-if "marker!=3DGroupID"><dtml-call "REQUEST.set('marker',GroupID)">
     Group <dtml-var GroupID>:
   </dtml-if>
<dtml-var Project>
</dtml-in>

Regards
Tino

> Thanks again,
> Philipp
>
>
> 	-----Urspr=C3=BCngliche Nachricht-----
> 	Von: Tino Wildenhain
> 	Gesendet: So 27.5.2001 17:38
> 	An: Philipp Robbel
> 	Cc: zope@zope.org
> 	Betreff: Re: dtml-Variablen in <dtml-in> loops?
> 	
> 	
>
> 	First of all, you dont have to cache SQL results via dtml-let.
> Zope
> 	does this already for you.
> 	
> 	If you have 2 queries:
> 	sqlGroupList:
> 	SELECT DISTINCT GroupID FROM Projects
> 	
> 	and the other:
> 	sqlProjectList(arg_GroupID)
> 	SELECT ProjectID, Project FROM Projects WHERE
> GroupID=3D<dtml-arg_GroupID
> 	type=3Dint>
> 	
> 	so you can:
> 	
> 	<dtml-in sqlGroupList>
> 	GroupID &dtml-GroupID;:
> 	 <dtml-in "sqlProjectList(arg_GroupID=3DGroupID)">
> 	  <dtml-unless sequence-start>,</dtml-unless>
> 	  <dtml-var Project>
> 	 </dtml-in>
> 	</dtml-in>
> 	
> 	This looks a bit cleaner imho ;)
> 	
> 	Regards
> 	Tino Wildenhain
>