Try building this query set in your view and use the .filter() method.
For example,
relevant_data =
ModelA.objects.filter(unique_field__in=ModelB.objects.all().values('unique_field'))
https://docs.djangoproject.com/en/dev/ref/models/querysets/#in
On Jul 30, 2012 7:27 AM, "Joris" <joris.bensc...@gmail.com> wrote:
> Dear list,
>
> Apologies in advance if this is a FAQ. I did extensive searching through
> this list and the django docs but have not been able to find a solution.
>
> I'm trying to display data from a postgres backend into a HTML table. Most
> of this data comes from a single table. Some columns however come from a
> highly complex raw SQL query that is very CPU-expensive to run. The two
> datasets cannot be combined into a single model for performance reasons.
> Both models do however have an identical unique field .
>
> As templates cannot do lookups into a dictionary or DB object, I now
> resort to doing a nested 'for' loop, where the template cycles through the
> whole dataset of model 1 for every record of model 2. Then if the unique
> field obtained from model 2 is found in model 1, the other valeus from
> model 1 are displayed. Below is the current code I use.
> This sounds hopelessly inefficient. Would someone be able to point me to a
> method to make this more logical?
>
> Many thanks
>
> Joris
>
> {% for GROUP in GROUPS %}
> <tr>
> <td>{{ GROUP.grnummer}}</td>
> {% for FIN in FINISH %}
> {% if FIN.grnummer = GROUP.grnummer
> %}<td>{{FIN.synthesis_finish}}</td>{% endif %}
> {% endfor %}
>
> </tr>
>
>
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