这里有多对多关系吗? The retail stores of SirenCD sell many different CD albums. An album can have one or more soundtracks. Each soundtrack has its track name, release date, genre, length and composer. Each album is associated with an artist. Customers can look up information about all artists, such as date of birth, biography and all his/her albums from the website of the company. The company provides a special service that allows customers to make their own CDs by providing a playlist to the company. These playlists can have tracks from different albums. The selection of soundtracks for these playlists are private to customers and are not visible to others. The price of such a customised CD is the sum of the prices of all soundtracks plus 30. Before being able to make purchases, a customer needs to register an account with the help of a retail store staff. The information needed for registration includes name, phone number, membership card number, address (for delivery, when needed) and the staff id who helped with the registration. The information about staff members consists of the staff id, name, the store he works in and the date of joining the store. After purchasing CDs, the customer will receive an invoice with the list of items he/she purchased. The information of invoices should also be stored in the database. You need to decide what to include in your database.
时间: 2024-04-24 11:21:16 浏览: 22
根据题目描述,存在以下多对多关系:
- Playlist与Soundtrack之间的关系:一个Playlist可以包含多个Soundtrack,而一个Soundtrack也可以出现在多个Playlist中。这是一个多对多关系,因为一个Playlist可以关联多个Soundtrack,同时一个Soundtrack也可以被多个Playlist使用。
需要注意的是,根据题目要求,Soundtracks的选择对于Playlists是私密的,即每个Playlist的Soundtracks对其他人是不可见的。因此,在数据库设计中需要考虑如何保护这种私密性。
其他关系包括:
- Retail Store与CD Album之间的关系:一个Retail Store可以销售多个CD Album,而一个CD Album可以在多个Retail Store中销售。这是一个多对多关系。在数据库设计中,可能需要创建一个中间表来记录Retail Store和CD Album之间的关联关系。
- Artist与Album之间的关系:一个Artist可以拥有多个Album,而一个Album只能属于一个Artist。这是一个一对多关系。
- Customer与Invoice之间的关系:一个Customer可以有多个Invoice,而每个Invoice只能属于一个Customer。这是一个一对多关系。
此外,还有其他一对多关系,例如:
- Customer与Registration之间的关系:一个Customer可以进行多次Registration,而每次Registration只属于一个Customer。这是一个一对多关系。
- Staff与Registration之间的关系:一个Staff可以帮助多个Registration,而每个Registration只能由一个Staff来帮助。这是一个一对多关系。
根据题目要求,数据库中还需要包括其他信息,如Artist、Soundtrack、CD Album、Customer、Invoice等的详细信息。具体的数据库设计需要根据需求进一步确定。
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