Question

1. Please answer the following questions. You need to draw ER diagrams using any free tools discussed in the class or you may draw using pencil and paper.

• Please identify the entities and relationships between them.
• For each entity, please identify the attributes each entity has.
• For each attribute, please identify whether this attribute is optional or required, single valued or multi-valued, simple or composite, stored or derived.
• Define a key (identifier) for each entity. Note that a key can contain multiple attributes (composite key).

b. A laboratory has several chemists who work on one or more projects. Chemists also may use certain kinds of equipment on each project. Attributes of CHEMIST include Employee ID (identifier), Name, and Phone No. Attributes of PROJECT include Project ID (identifier) and Start Date. Attributes of EQUIPMENT include Serial No and Cost. The organization wishes to record Assign Date—that is, the date when given equipment item was assigned to a particular chemist working on a specified project. A chemist must be assigned to at least one project and one equipment item. Given equipment item need not be assigned, and a given project need not be assigned either a chemist or an equipment item.

Answer 1

A chemist must be using atleast one equipment whereas an equipment can/cannotbe assigned to an employee too.Relationship between employee and equipment is zero or One-to-one Or Many realtionship and its represented by

Given an employee must be assigned to atleast one project or more,where as a project can or cannot be assigned to any employee.So relationship is Zero or One-to-Zero or Many relationship and is represented by

Given an Equipment cannot be assigned. The relationship between Project and equipment is Zero or One-to- Zero or Many relationship and is represented by

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