MerginMaps / MerginMaps/mobile

Relationship strength "composite" has no effect in the app

Open
#2,315 9 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

enhancement forms relations
Dominant language
C++
Stars
388
Forks
87
Avg merge
2d 7h
Merged PRs (30d)
20

Description

Setting a 1-n relationship in QGIS is saved in the .qgz project file. There is an option to set the strength of the relationship as shown in the Mergin docs. Using the Association setting allows deletion of the parent while child data persists. Changing this to Composition allows for cascading deletes in QGIS (if a parent is deleted child items are also deleted). QGIS will pop up a warning as to which child items from which table will be deleted.

This behaviour is not the same in Input. Regardless of relationship strength setting, deleting a parent feature will not delete child items. This leads to orphans in the related table.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the one-to-many relationship in QGIS with Composition strength, save it in the .qgz project, and compare deletion behavior in Input. Trace the parent deletion path and relationship handling, then verify that deleting a parent cascades to its child items without leaving orphaned related records.

Written by the indexing model from the issue text.

Assessment

Domain
mobile-dev
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.