Bug report #21895
Default values and expression calculator not working together
| Status: | Open | ||
|---|---|---|---|
| Priority: | Normal | ||
| Assignee: | - | ||
| Category: | Vectors | ||
| Affected QGIS version: | 3.4.3 | Regression?: | No |
| Operating System: | Easy fix?: | No | |
| Pull Request or Patch supplied: | No | Resolution: | |
| Crashes QGIS or corrupts data: | No | Copied to github as #: | 29710 |
Description
While trying to work around #21892 I encountered the following.
To replicate (in a GeoPackage - probably not format specific):
1) Create a new field of type Integer called whatever (_MY_FIELD here)
2) Use the Layer Properties -> Attributes Form to set a default value of 0 on _MY_FIELD, and tick the "Apply default on update" (this is the bug!)
3) Now, use expression calculator to UPDATE _MY_FIELD with any numerical value (fid will do).
Result = _MY_FIELD only has values of "0".
If you uncheck the "Apply default on update" then the update of the field will work as expected.
History
#1
Updated by Jürgen Fischer over 5 years ago
- Description updated (diff)
#2
Updated by Giovanni Manghi over 5 years ago
- Category changed from Field calculator to Vectors
#3
Updated by Giovanni Manghi over 5 years ago
On the other hand the default does not do completely his job in other situations, like #21868
#4
Updated by Jonathan Moules over 5 years ago
I ended up having to work around it with a logical if statement:
if("NEW_VALUE" is null, "NEW_VALUE", 0)
But only a workaround.