Hello, I am a student and I was assigned to create my first entity relationship diagram and I'm kind of lost. The professor hints the paintings should be broken into a generalization hierarchy since they have so many attributes but I can only break them into two sub(entities) based on my understanding of G.H.(using the "is a" rule)
Anyway I'm struggling with that and finding the weak entity(professor also hinted that there is a week entity)
I attached what I have so far as ERD1.pdf (didn't establish relationship type/participation constraints yet)
Am I even on the right track/have the right idea?
The prompt is below:
The BestArt museum, which owns several millions artifacts, has asked you to do the conceptual design of a database for the following information requirements.
The only artifacts of the museum in its database will be paintings. Each painting is uniquely identified by an artifact number. Data about each painting include a name, year completed, year acquired by the museum, estimated value, and a “school” (e.g. Cubism). Each painting was created by one painter, although the painters of some paintings are unknown. Due to shortage of exhibit rooms, the least valuable paintings are kept for long period of time in storage rooms, whereas the most valuable ones are shown in exhibit rooms. A room is identified by a unique room number and has a size (in square feet).
Some of the BestArt paintings may be on loan to allied museums, typically for several months. BestArt may also have temporary possession of paintings loaned to it by allied museums. They are shown in exhibit rooms alongside BestArt paintings, typically for several months. Each allied museum has a unique name, a city, a state, and a curator (with whom BestArt negotiates loans). Paintings loaned to BestArt or by BestArt will also be in the database and will have the same attributes as the paintings owned by BestArt, plus a return date
Customers of BestArt consist of members and non-members. Members may be VIP or regular members. VIP may be benefactors and/or docents. Benefactors have a level (e.g., silver, gold, …). There is an expiration date for regular members. A docent may have one or several specialties, such as cubism and impressionism. A docent may volunteer to be present at certain dates and times in a specific room to explain the room paintings to visitors. In honor of a painting loaned to BestArt, there may be one or several gala-nights at different dates, with invitations to some benefactors. BestArt also organizes art-nights. An art-night will involve a discussion about one painter by one docent. A date and time is specified. Non-members who wish to attend art-nights are required to register in advance. A museum room may or may not be specified for an art-night.
The following data is assumed for all persons in the database: a unique id, a name, sex, year of birth, year of death (when applies), country of birth.
what I consider to be his hints
2. As discussed in class concerning the qualities of an ERD, completeness is more important than simplicity. For example, if the information requirements describe in some length different categories of PAINTINGs, with different relationships to other entities, maybe that tells you if your ERD should have a single entity or a Generalization Hierarchy.
- Do not spend too much time in trying to identify early on a weak entity and an associative entity, if you have trouble with them. Good GH and relationships come first. (you can still get an A, albeit with a slightly lower score, without the correct weak entity and associative entity).
Thanks in advance to anyone who can help!
