ER DIAGRAM SEARCH ENGINE | Editable Entity Relationship Diagram Template on Creately
Search ▾. Search Entities · Tags · Top CD Stubs. Documentation ▾ Each primary entity has a main table with the same name as the entity, containing its An artist is generally a musician, a group of musicians, or another music This schema diagram shows the core database tables and relationships between them. A Entity Relationship Diagram showing ER DIAGRAM SEARCH ENGINE. You can edit this Entity E-R Diagram of Library Management System. (9). This paper presents an extended entity-relationship model for structured musical databases. Keywords: musical database, musical search, musical anal- ysis, object-relational model of music that is suited for an object-relational database .
Entity Relationship Modeling Examples - Learning MySQL [Book]
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.
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.
BBC Bitesize - GCSE Digital Technology (CCEA) - Database development - CCEA - Revision 2
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.
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. 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. When he finishes the course, a grade such as A or B and a mark such as 60 percent are recorded. Each course in a program is sequenced into a year for example, year 1 and a semester for example, semester 1. Although it is compact, the diagram uses some advanced features, including relationships that have attributes and two many-to-many relationships.
The ER diagram of the university database In our design: Each student must be enrolled in a program, so the Student entity participates totally in the many-to-one EnrollsIn relationship with Program.
A program can exist without having any enrolled students, so it participates partially in this relationship. As a weak entity, Course participates totally in the many-to-one identifying relationship with its owning Program.
This relationship has Year and Semester attributes that identify its sequence position. Student and Course are related through the many-to-many Attempts relationships; a course can exist without a student, and a student can be enrolled without attempting any courses, so the participation is not total.
When a student attempts a course, there are attributes to capture the Year and Semester, and the Mark and Grade.
Learning MySQL by Hugh E. Williams, Saied M.M. Tahaghoghi
For a real university, many more aspects would need to be captured by the database. The airline has one or more airplanes. An airplane has a model number, a unique registration number, and the capacity to take one or more passengers. 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. They all have the same structure: These tables are used to store those mappings. They are used to redirect one MBID to another when entities are merged. Two of them are shown in the diagram. There are two tables that help to avoid unnecessary duplication: Each AR attribute either applies to a particular AR or it doesn't.
They can only be modified by the AR editors. AR types are arranged in a number of trees, for ease of finding.