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er_prac - Entity-Relationship Model[ER Model OUTLINE...

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Entity-Relationship Model [ER Model]
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OUTLINE box4 Overview of Database models box4 ER Diagram for COMPANY Schema box4 Constraints box4 Structural Constraints
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Overview of Database Design Process box4 Two main activities: square6 Database design square6 Applications design box4 Focus in this session on database design square6 To design the conceptual schema for a database application box4 Applications design focuses on the programs and interfaces that access the database square6 Generally considered part of software engineering
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Overview of Database Design Process
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Example COMPANY Database box4 The company is organized into DEPARTMENTs. Each department has a name, number and an employee who manages the department. We keep track of the start date of the department manager. box4 Each department controls a number of PROJECTs . Each project has a name, number and is located at a single location. box4 Store each EMPLOYEE’s social security number, address, salary, sex, and birthdate. Each employee works for one department but may work on several projects. We keep track of the number of hours per week that an employee currently works on each project. We also keep track of the direct supervisor of each employee. box4 Each employee may have a number of DEPENDENTs. For each dependent, we keep track of their name, sex, birthdate, and relationship to employee.
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Initial Design – COMPANY box4 Based on the requirements, we can identify four initial entity types in the COMPANY database: square6 DEPARTMENT square6 PROJECT square6 EMPLOYEE square6 DEPENDENT
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Initial Design – COMPANY
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