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<p>Dear all,</p>
<p>As a learning experience I am trying to make an application that
was developed with python 2 and qgis 2 with a postgres backend of
vs 9.3 work with python 3/qgis 3/postgres 13.</p>
<p>As expected, there are plenty of places where it is still not
working as it should, but I have managed to upgrade the database,
open the project file in qgis 3.16, and all the layers (based on
views) have loaded correctly. The relationships that were stored
in the project file also seem to be working correctly with the
existing .ui files. I can open the parent layer form, and in the
child form I can see the foreign key reflected properly, and
changing as the selected parent feature is changed. All the
relationship settings were set manually and stored in the project
file. When I change the column preview on the left hand side of
the form from parentid to any other column, the child form still
shows the parentid correctly.</p>
<p>For testing/learning purposed I did the whole process manually
from scratch in 3.16. When I now open the parent layer form, and
set the column preview on the left of the form to anything else
than the parentid, in the child form, where I would have expected
the parentid as before, it shows the column used in the column
preview.</p>
<p>Is this the expected behaviour? Is it possible to set this to the
'old' behavior? If so, can that also be done using python
(ultimately I want to load the layers and create the relationships
in python)? Below some screenshots to clarify what I described.<br>
</p>
<p>Thanks for your help,</p>
<p>Janneke</p>
<p>Original situation (A), behaviour as expected:</p>
<p>A) With locationid as column preview shows corresponding
locationid in child form (the number 1)<br>
</p>
<p><img src="cid:part1.51133ECD.36B7640C@gmail.com" alt=""><img
src="cid:part2.BC9F89D4.17F83979@gmail.com" alt=""></p>
<p>The same when changing the column preview: (now locationid in
child form is number 11288)<br>
</p>
<p></p>
<p><img src="cid:part3.3C79F81C.1B434CAD@gmail.com" alt=""
width="173" height="72"><img
src="cid:part4.712463A3.06B127F4@gmail.com" alt="" width="292"
height="70"></p>
<p>B) Manually newly created relationships, with column preview of
the parent id shows it in the child form (note that there seems to
be a box in front of another box, in another situation I have seen
it looking like a greyed out combo box)<br>
</p>
<p><img src="cid:part5.087ABD75.D1C8D1F5@gmail.com" alt=""><img
src="cid:part6.947FB361.31BBE2B9@gmail.com" alt=""></p>
<p></p>
<p>With the newly created relationship, when selecting districtid as
a column preview, it is the district id that is shown in the child
form, not the locationid.<br>
</p>
<p><img src="cid:part7.9989E74F.6D3D6E7C@gmail.com" alt=""><img
src="cid:part8.71877B4D.2BEA4328@gmail.com" alt=""></p>
<br>
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</p>
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