MusicBrainz Database / Schema - MusicBrainz
This section explains the requirements for our three example databases— music , university, and flight —and shows you their Entity Relationship diagrams. This is actually a site with many simple data models. search for something like example database model music you will find other examples. Mar 18, The Music Database project is to categorize and catalog every single Tables In ER- Diagram The Most Important Tables in our project: Function to deactivate a user id if he has not used the website for a long time;
Song "Into the Blue" by "Moby" -- all the recordings listed above will be linked to this object Secondary entities Each secondary entity has a main table with the same name as the entity, containing its basic data. List of artists, variations of artist names and pieces of text to join the artist names. It contains information about the format of the media, its position in the release, an optional title, and most importantly, a list of tracks.
It has an MBID, and contains a link to a recording, a title, artist credit and position on its associated medium. Schema The SQL scripts that create the schema can be found in our source code repository. This schema diagram shows the core database tables and relationships between them.
Core entities are blue, mostly-static lists are yellow, and external identifiers are red. There is also a higher resolution schema diagram.
They contain the alternate names for instances of those entities. Supertype-subtype clusters can be of two kinds: Comes about when an instance of the superentity type must always have one and only one subtype counterpart; therefore, the potential subtype occurrences in question are mutually exclusive. This is the kind that concerns to your scenario. A typical case in which an exclusive supertype-subtype comes about is a business domain where both an Organization and a Person are considered Legal Parties, like in the situation deliberated in this series of posts.
Presents itself when a supertype instance may be complemented by multiple subtype occurrences, each of which is compelled to be of a different category. An example of this kind of supertype-subtype is dealt with in these posts.
It is worth mentioning that supertype-subtype structures —being elements of a conceptual character— do not belong to a specific data management theoretical framework, be it relational, network or hierarchical —each of which offers particular structures to represent conceptual elements—.
It is also opportune to point out that although supertype-subtype clusters bear a certain resemblance to object-oriented application programming OOP inheritance and polymorphism, they are in fact distinct devices because they serve different purposes.
In a database conceptual model —that must represent real world aspects— one deals with structural features in order to describe informational requirements, whereas in OOP polymorphism and inheritance, among other things, one a sketches and b implements computational and behavioural characteristics, aspects that decidedly belong to appplication program design and programming.
In this respect, an application programmer may typically create, e. Using entity-relationship constructs to represent a conceptual model with supertype-subtype structures You asked for an entity-relationship diagram ERD for brevity but, although being an extraordinary modeling platform, the original method —as introduced by Dr. Peter Pin-Shan Chen2— did not supply enough constructs to represent scenarios of the sort being discussed with the precision that a proper database conceptual model requires.
Consequently, it was necessary to make some extensions to said method, situation that yielded results in the development of an approach that assists in the creation of enhanced entity-relationship diagrams EERDs that, naturally, enriched the initial diagramming technique with new expressive characteristics. One of those characteristics is, precisely, the possibility of depicting supertype-subtype structures.
Elmasri and Shamkant B.
It is also available as a PDF that can be downloaded from Dropbox. An album contains one or more tracks Artists, albums, and tracks each have a name. Each track is on exactly one album. Each track has a time length, measured in seconds. When a track is played, the date and time the playback began to the nearest second should be recorded; this is used for reporting when a track was last played, as well as the number of times music by an artist, from an album, or a track has been played.
Music Library Database by Joban Sidhu on Prezi
Conversely, each play is associated with one track, a track is on one album, and an album is by one artist. The attributes are straightforward: The track entity has a time attribute to store the duration, and the played entity has a timestamp to store when the track was played. If you wanted to use the music database in practice, then you might consider adding the following features: Support for compilations or various-artists albums, where each track may be by a different artist and may then have its own associated album-like details such as a recording date and time.
Under this model, the album would be a strong entity, with many-to-many relationships between artists and albums. Playlists, a user-controlled collection of tracks. For example, you might create a playlist of your favorite tracks from an artist. Track ratings, to record your opinion on how good a track is. Source details, such as when you bought an album, what media it came on, how much you paid, and so on.
Album details, such as when and where it was recorded, the producer and label, the band members or sidemen who played on the album, and even its artwork. Smarter track management, such as modeling that allows the same track to appear on many albums. The University Database The university database stores details about university students, courses, the semester a student took a particular course and his mark and grade if he completed itand what degree program each student is enrolled in.
Learning MySQL by Hugh E. Williams, Saied M.M. Tahaghoghi
We explain the requirements next and discuss their shortcomings at the end of this section. Consider the following requirements list: The university offers one or more programs. A program is made up of one or more courses.Entity Relationship Diagram (ERD) Tutorial - Part 1
A student must enroll in a program. A student takes the courses that are part of her program. A program has a name, a program identifier, the total credit points required to graduate, and the year it commenced. A course has a name, a course identifier, a credit point value, and the year it commenced. Students have one or more given names, a surname, a student identifier, a date of birth, and the year they first enrolled.