[Zope] ZSQLMethod conditional insert

[David Pratt]

Hi Thomas. I would say postgres is better for this sort of thing.  In 
postgres, you can write a function in plpgsql or other function 
language (there is also a python function language) that you install in 
postgres. In any case once you write it and then call it - it is 
executed in a single transaction.  You are only left with selecting the 
function in your zsql from your script. It is hard to comment on the 
method you have sketched out not knowing what arguments you are passing 
into the method. You have identified path but I see others that you 
haven't discussed so don't really know where you plan on getting them 
from.

Regards,
David


On Wednesday, July 27, 2005, at 03:22 PM, Thomas Olsen wrote:

> Hi
>
> This is probably an FAQ but I haven't been able to find and answer.
>
> I need a counter for a certain CMFType and want to store the hits in a 
> MySQL
> database not to fill up the ZODB. I've checked to two suggestions 
> below but
> they both use two ZSQLMethods first to check if the URL is already in 
> the
> table, then to do the actual update or insert.
>
> http://www.zope.org/Members/element/Simple_SQL_Page_Counter
> http://zopelabs.com/cookbook/991116439
>
> I'd like to be able to do that just in one ZSQLMethod for efficiency 
> but I
> cant seem to figure out a way of doing it.
>
> The table is very simple:
>
> CREATE TABLE mostread (
>   path varchar(255) NOT NULL default '',
>   num bigint(20) NOT NULL default '0',
>   dt datetime NOT NULL default '0000-00-00 00:00:00',
>   PRIMARY KEY  (path)
> )
>
> For now my ZSQLMethod get the argument "path" which is a relative URL 
> and it
> looks like this:
>
>   select @lastval:=num from mostread where <dtml-sqltest path 
> type="string">
>   <dtml-var sql_delimiter>
>   update mostread set num=@lastval+1, dt=now() where <dtml-sqltest path
> type="string">;
>   </dtml-if>
>
> But that naturally only works if there is already a record containing 
> "path".
> What I want to do is something like this (pseudo-code):
>
>   select @lastval:=num from mostread where <dtml-sqltest path 
> type="string">
>   <dtml-var sql_delimiter>
>   <dtml-if "sequence-length > 0">
>     update mostread set num=@lastval+1, dt=now() where <dtml-sqltest 
> path
> type="string">;
>   <dtml-else>
>     insert into mostread(path, num, dt)
>       values(<dtml-sqlvar path type="string">, 1, now())
>   </dtml-if>
>
> Is there a way of doing this or should I just create that extra 
> ZSQLMethod?
>
> -- 
> Med venlig hilsen
>
> Thomas Olsen
> http://www.headnet.dk
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