db schema for storing multiple choices user settings

Question

I am working on a project with the following data structure :

datamodel

A user need to be able to perform personal filtering on a given project, and this filtering needs to be saved (for each user/project pair). For example, he can choose to filter based on attribute1, attribute 2.

For storing such user settings, I did use this schema:

enter image description here

and I can have for example a setting for attribute1 filtering, and in my user_setting table store the corresponding value.

My problem is that the user needs to be able to perform a manual filtering on the objects (i.e. filtering them with checkbox). That would result in choosing objectIDs among all the object IDs.

My first thought was to store them in setting_value as comma separated values, but I read that I should not denormalize (note that there can be a lot of objects, and a lot of projects).

Is it a good approach or should I rethink my user setting storage approach?

Answer 1

Since you need to use the IDs of manually selected objects to query those objects, it would be counter-productive to store them as a single column value. I would probably choose to store the manually selected object IDs in their own table.

• cicero: Good point about the fact that I will need to query the IDs, so my table would be something like |id|project_id|user_id|selected_object_id| resulting in one row for each selected ID, that would result in a very large table since there could be a lot of users/project combinations, is that a problem regarding any performance issues ?
• mustaccio: Performance concerns can only be answered by simulation testing. "very large table" is a subjective measure.