[mod_python] Pager component, and Count of Elements...

durumdara durumdara at gmail.com
Thu Oct 5 06:00:47 EDT 2006

Hi !

I wrote some mails about this theme, but I forgot to ask an important 
How to I get the number of elements in the query... ?

These valued needed for the Pager:

   1. "Split by" - the max. record number you can see in the page.
   2. "RecordCount" - how many records you have (total) - to calc number
      of pages.
   3. "ThumbCount" - how many page thumb (link) you see in one page.
   4. "Actual Page Number" - where are we in the page collection.

Simply I get every of these values except RecordCount. To get it, I must 
count the records in the full query...
I have many elements (1000, 10000 or 100000), so I don't want to fetch 
them all.
Because this I need to exec the query in twice, because I need to get 
the count of elements, and I need some elements from it.

1.) select count(*) from ...
2.) select * from ...

Some of the databases supports "repeatable read" transaction isolation, 
and they are protect the view to I get same thing in different times.
But if database not supports this, I can get different values with these 
queries - example: new record inserted after COUNT(*), so number of the 
elements is greater than in the first query...

How do you handle this problem in MySQL, or other database that cannot 
isolate the transactions (example) ?

Thanks for your help:

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