Bug report #13490
PostGIS: Merge drops dataset whereas split retains it
|Affected QGIS version:
|Pull Request or Patch supplied:
|end of life
|Crashes QGIS or corrupts data:
|Copied to github as #:
- splitting a feature in two new features, the database receives an UPDATE and an INSERT statement - OK
- merging two features together, the database receives two DELETE and one INSERT statement. I would expect one DELETE and one UPDATE statment. Thus you could retain the primary key of a feature which is crucial if other tables have a foreign key constraint on the table being edited.
#1 Updated by Jürgen Fischer over 8 years ago
- Category changed from Data Provider to Vectors
- Status changed from Open to Feedback
I don't think this is a bug, but it's not a provider issue. The algorithm merges the two features, deletes them and insert a new one. Both could have relations and we don't have a way/feature to choose which one of the two should survive.
#2 Updated by Bernhard Ströbl over 8 years ago
Jürgen Fischer wrote:
I don't think this is a bug, but it's not a provider issue. The algorithm merges the two features, deletes them and insert a new one.
I did not really know where to put it, so the algorithm is supposed to be changed then. If merge is regarded being the opposite of split, the two should behave similar.
Both could have relations and we don't have a way/feature to choose which one of the two should survive.
Oh, there is a way already implemented: When you merge features a dialog opens where you can decide which attribute set you want in the new feature. So if you decide for one of the two pk values that would be the one to be updated.
#8 Updated by Bernhard Ströbl over 7 years ago
Sandro Santilli wrote:
I don't think we can call this bug to cause a "corruption". It's an editing operation, just doesn't behave as the user is expecting.
The corruption comes from foreign key constraints defined with ON DELETE CASCADE => related datasets in other tables are thus deleted! If you defined them ON DELETE RESTRICT you would not be able to merge at all.
#10 Updated by Giovanni Manghi almost 5 years ago
- Resolution set to end of life
- Status changed from Open to Closed
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