Lyric Music is an ecommerce company that provides web services to music artists. Among its services are offering mp3 and Real A udio files for download, selling CDs, and developing promotional materials for artists.
Lyric Music Data
A database can be described in more than one way. One technique is to simply list the rows and columns of each table. These are shown below.
The Artists table holds information about each artist. An artist could be a band or group. It could also be a solo artist.
The Members table holds information about the individuals who are members of each artist group. See the table on the facing page.
An artist (band) may have several members. But also a member may be part of more than one artist group. For instance Band X may have four members, one of whom also works as a solo artist. A crossreference (xref ) table is needed to maintain this complex relationship between artists and members. XrefArtistsMembers is that table. Its primary key is a combination of
MemberID and ArtistID, so it can match any artist with any member and viceversa. The
RespParty is a Yes/No field that identifies which of each artist’s members is the person responsible for paying bills and receiving official correspondence from Lyric Music.
The Titles table tracks information on each CD title produced by each artist. ArtistID is a foreign key that relates this table to Artists.
Each CD title can have multiple tracks. The primary key of this table is the combination of
TitleID and TrackNum. The mp3 and RealAud fields are Yes/No fields that indicate whether that track is available in mp3 or Real Audio formats.
Each title is classified according to its genre. The Genre table is a simple lookup table that lists the valid genres.