zgm 2 个月前

    zgm 2 个月前
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    zgm 3 个月前
    此条为私密说说,仅发布者可见
    zgm 3 个月前

    Question 2:
    A fitness center aims to setup a database to maintain the following information.
    The database stores the name, the address and a unique ID of each employee. The employees are classified into the three categories: trainers, administrators and technicians. Each trainer has one or more specialties, e.g., weight gain, weight loss, strength building, etc. An administrator can help to register new members and can be reached through a landline phone number. Each member is identified by their email address. The fitness center organizes fitness classes for members. Each class has a name, a start date, an end date and a daily time slot. No two fitness classes have the same daily time slot, and for each fitness class the start date must be before the end date. A member may choose to participate in one or more fitness classes and may also choose one of the trainers as their personal trainer. Each fitness class is instructed by only one trainer and not all trainers deliver fitness classes. After receiving the approval from an administrator, a member may choose to add multiple associate members who will have partial access to the services provided by the fitness center, and an associate number (i.e., 1, 2, . . .) and the name of each associate member are recorded in the database. The database keeps track of all equipment available in the fitness center. Each piece of equipment has a unique ID and must have one of the following three status types: new, working or broken. Each technician has a mobile phone number. Technicians maintain equipment in the fitness center and the database records the date and the report of each maintenance event. Each piece of equipment should be maintained at least twice a year.
    You need to draw an ER (or EER) diagram to capture the data requirements (if possible) through the following exercises (1)-(5):
    (1) Identify the entity types. (2) Identify the relationship types. (3) Identify the attributes of the entity and relationship types. (4) Identify a primary key for each entity type. (5) Identify cardinality ratios or participation constraints, if any. You also need to
    • state the necessary assumptions, if any, to make your modelling solutions complete.
    • identify the requirements that cannot be captured in an EER-diagram.

    zgm 3 个月前



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