Simple database feature

Is it possible to link a simple database to mocp?
I would like to search in my collection by author, title, performer and then to have this and some additional information displayed during reproduction.
I would like not to use Id3 tags or other tagging methods but to use a separate database file.
Thanks for your help.

Hi, MOC uses a database to cache files' tags.
There are two possibilities how to tie your database to MOC, depending on its format/engine.
Either, you can always convert it to MOC's (Berkeley DB's) format; or make MOC understand your database, i.e. write support for it.
A separate pane/screen for displaying metadata would have to be written, but I would love it.

PS: Another approach is to hack on/reimplement tagsfs ( - website down at the moment), which I'm intending to do one day. tagsfs basically generates a virtual filesystem with your music divided by author, title, album, and then alphabetically. It also supports some sort of searching.
PS2: By no means I foresee MOC having a music library. MPD is there for this purpose.

In fact, despite I have been using moc for a long time and I like it's user interface better than mpd's one, my first idea was to use mpd which has a builtin database. I asked the developers mailing list and they answered that, by design, mpd's database can use only information from the id3 tags.
I will take a look at the database file and try to figure out how to add information to it.
Is there an option to tell mocp not to modify the database file?

I think making the database file read-only suffices :-), although there might be some errors when MOC tried to write data.
What is your DB engine? MySQL or similar? If so, db_sql tool might be of use:

I was able to open the database file using db_create() and bdp->open() of libdb4.6. Now it seems I need information on the sruct used for the data, I was not able to find it in the moc sources.
Could you give me a pointer to the routine in which the database file is written?

Metadata handling is done in tags_cache.c.
Almost at the beginning you have the structure:
56: struct cache_record
57: {
58: time_t mod_time; /* last modification time of the file */
59: time_t atime; /* Time of last access. */
60: struct file_tags *tags;
61: };

And later on, you find serializing functions:
171: static char *cache_record_serialize (const struct cache_record *rec, int *len)
231: static int cache_record_deserialize (struct cache_record *rec,
232: const char *serialized, const size_t size,
233: const int skip_tags)

Hope this helps.

I am afraid I was looking at the wrong MOC version (2.4.4), there is no cache_record structure but there is a cache_list_node struct which looks similar.
I downloaded 2.5.0-alpha4 and cache_record is there.