Assign an Icon to a file ?

I assigned a filetype with an Icon to a sqlite file.

I set it as Editor somewhere in the project (This Computer / MacOS).

The file extension is .sqlite.

As UTI, I used public.database (it was: public.database.sqlite.

I even open Get Info for one of the files and set my application as the default owner (so when I double click the document, it is open with my application).

I shutdown the computer, wait a but while drink a coffee, poser it ON, open the folder where my document files resides and these docments still have the undefined Icon.

Did I forgot something ?

Edit: I forgot to say that I set all Icons sizes and masks.