== Blueprint for Many-to-Many ==

* http://www.tomjewett.com/dbdesign/dbdesign.php?page=manymany.php

We need Many-to-Many support for [wiki:BluePrintGISFeatureLayers GIS Feature Groups] (to be able to select a mixture of Feature Classes &/or individual Features) & for the [wiki:BluePrintPersonRegistry Person Registry] & [wiki:BluePrintOrganisationRegistry Organisation Registry]

Web2Py doesn't really support Many-to-Many SQL tables.[[BR]]
- even though the t2_membership table is one

It can kind-of do it using Tagging widgets:
 * t2.tag_widget()
 * [http://groups.google.com/group/web2py/browse_thread/thread/a234895207097f60/ multiple=True]

These are great for selecting between a relatively small number of options (the second supports the [http://lab.arc90.com/tools/jquery_multiselect jquery multiselect plugin]).[[BR]]
However they aren't scalable & also don't have proper referential integrity.

I think the ideal should be something like:
 * http://code.google.com/p/django-ajax-filtered-fields/

If we can make something generic enough then Massimo will be keen to incorporate it.

My request to Web2Py list:
 * http://groups.google.com/group/web2py/browse_thread/thread/414fd05976f97226/
Other pertinent posts:
 * http://groups.google.com/group/web2py/browse_thread/thread/89b117d74c611747

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BluePrints