[Digikam-devel] What do we want to store in the database?

[Marcel Wiesweg]

> Correct me, if I'm wrong, but I think, that fields should be stored in
> table like Fields (with cols: field_id, name, description?) and there
> will be separate table FieldValues (image_id, field_id, value). To have
> the ability to store some fields as numbers, int_value column can be
> added to FieldValues and maybe some flag column to Fields table, to mark
> that this field is numerical.
>
> For fields that require many-to-many relationship (multiple comments)
> there will be more entries with same image_id and field_id but different
> value.

What you describe is - thought to its end - just what strigi/nepomuk are 
doing: storing of triples of information, and ontology to describe what can 
and shall be stored for a type of file.

This is a very general approach.
For digikam, I see the database more as a tool that we use rather than a 
general description of the data, so we know what we store, what format it 
has, and where it is stored.
We must keep complexity low!

>
> So this thread, as I understand it, is about default rows in Fields
> table. Tags use almost same db schema now - they could be merged and
> tags can be viewed as user defined fields with no value and tree
> structure (in separate table representing tree relations). (and as I
> have proposed few days before, albums & groups can be treated same way).
>
> Tibor Blenessy