The Structure
A picture is worth a thousand words, so a study of the Entity-Relation Diagram for this database may be enlightening!
This diagram shows the entity relations for the whole database. The following notes should help in the understanding of some of the more peculiar choices made when setting up this structure.
Coded fields
- There are a relatively small number of formations and variations on the number of people in a dance. Consequently, these fields have been represented with a code to allow more compact storage and greater efficiency. It also improves the consistency of the database and increases the ability to validate the information. The database includes relations to map between these codes and a textual representation of the information.
Owner defined codes
- A secondary entity has been introduce to link records and owners, making it possible to allow each owner to have an owner defined code for a particular record. This was introduced to caters for some of the clubs where I call, which use an index number for each of their records. You may also find this useful.
Uniquely identifying dances and music
- The name of a dance or a piece of music is not sufficient
to uniquely identify a particular dance or tune, since the folk
process has often resulted in variations in names. In addition,
there are occasionally totally different dances or tunes with
the same name. For this reason the database uses a triad of domains
to uniquely identify each dance or tune -- the name, a number
which allows distinction between totally different entities of
the same name and a number for the version which allows for distinction
between similar versions of the same entity.
- Although the database includes this capability, the current version makes very little use of it: distinguishing between versions require a lot more time than I have been able to put in.
- Due to the ridiculously comprehensive U.K. data protection laws it is not legally possible for me (or you) to store personal information without registering (and paying a fee) for the privilege, even with the subject's permission. I believe that some of the information that ought to be contained in the source_owner, record_owner and owners relations may be covered by the D. P. Act, and so I cannot hold it or pass it on to you. I do not believe that information about institutions is covered, so at least I can pass on the information about libraries. For the moment at least, those of you who receive this database on paper can, of course, receive, maintain and pass on this 'personal' information: a ridiculous situation isn't it?
- This database structure shown in the diagram results in the following relations and domains:
Relation Comment Domains (Fields) couple_map Maps the coding to a text description of the number of people couple_code, couples danceAltName_dance Alternative titles for dances alt_dance_name, main_dance_name, dance_different dance_comment Comments on a dance dance_name, dance_different, dance_version, dance_comment, dc_author dance_music Links a dance to a particular piece of music dance_name, dance_different, dance_version, music_name, music_different, music_version, phrases, bibtex_key dance_source Links a dance to the sources in which it is published dance_name, dance_different, dance_version, bibtex_key, location dances The information about a particular dance dance_name, dance_different, dance_version, couple_code, formation_code, dance_level, dance_type, dance_author, dance_props, bars, music_type formation_map Maps the coding for a formation to a textual description formation_code, formation musicAltName_music Alternative titles for pieces of music alt_music_name, music_name, music_different music_comment Comments on a piece of music music_name, music_different, music_version, music_comment, mc_author music_source Links a piece of music to the sources in which it is published music_name, music_different, music_version, bibtex_key, location, key musics The information on a particular piece of musics music_name, music_different, music_version, music_type, phrase_length, music_props, composer owners The people whose collections I have catalogued owner_name, full_name record_owner Links a record to the person who owns it record_code, owner_name, owner_code recordings Links a piece of music to a recording of it music_name, music_different, music_version, record_code, side, track records Information on records (CDs etc.) record_code, record_name, artist, medium source_owner Records who owns which sources bibtex_key, owner_name sources Information on a printed source bibtex_key, full_name tracks Gives details of the pieces of music on a particular record record_code, side, track, track_name, style, music_type, intro, times, bars, outro - The various domains are described in the next section on the data dictionary.
- Although the database includes this capability, the current version makes very little use of it: distinguishing between versions require a lot more time than I have been able to put in.
