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Chapter 3. Data Modeling Using the Entity-Relationship Model. FIGURE 3.1 A simplified diagram to illustrate the main phases of database design. FIGURE 3.2 An ER schema diagram for the COMPANY database. FIGURE 3.3 Two entities, employee e 1 and company c 1 , and their attributes.
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Chapter 3 Data Modeling Using the Entity-Relationship Model
FIGURE 3.1A simplified diagram to illustrate the main phases of database design.
FIGURE 3.3Two entities, employee e1 and company c1, and their attributes.
FIGURE 3.6Two entity types, EMPLOYEE and COMPANY, and some member entities of each.
FIGURE 3.7The CAR entity type with two key attributes, Registration and VehicleID.
FIGURE 3.8Preliminary design of entity types for the COMPANY database.
FIGURE 3.9Some instances in the WORKS_FOR relationship set, which represents a relationship type WORKS_FOR between EMPLOYEE and DEPARTMENT.
FIGURE 3.10Some relationship instances in the SUPPLY ternary relationship set.
FIGURE 3.11A recursive relationship SUPERVISION between EMPLOYEE in the supervisor role (1) and EMPLOYEE in the subordinate role (2).
FIGURE 3.15ER diagrams for the COMPANY schema, with structural constraints specific using (min, max) notation.
FIGURE 3.16The COMPANY conceptual scheme in UML class diagram notation.
