ER model

Entity-Relationship Model ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Entity Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Entity Sets customer and loan customer-id customer- customer- customer- loan- amount name street city number

Attributes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Example: customer = (customer-id, customer-name, customer-street, customer-city) loan = (loan-number, amount)

Relationship Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Relationship Sets (Cont.) ,[object Object],[object Object]

Degree of a Relationship Set ,[object Object],[object Object],[object Object],[object Object],[object Object]

Mapping Cardinalities ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Mapping Cardinalities One to one One to many Note: Some elements in A and B may not be mapped to any elements in the other set

Mapping Cardinalities Many to one Many to many Note: Some elements in A and B may not be mapped to any elements in the other set

Mapping Cardinalities affect ER Design ,[object Object],[object Object]

E-R Diagrams ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

E-R Diagram With Composite, Multivalued, and Derived Attributes

Relationship Sets with Attributes

Roles ,[object Object],[object Object],[object Object],[object Object]

Cardinality Constraints ,[object Object],[object Object],[object Object],[object Object]

One-To-Many Relationship ,[object Object]

Many-To-One Relationships ,[object Object]

Many-To-Many Relationship ,[object Object],[object Object]

Participation of an Entity Set in a Relationship Set ,[object Object],[object Object],[object Object],[object Object],[object Object]

Alternative Notation for Cardinality Limits ,[object Object]

Keys ,[object Object],[object Object],[object Object],[object Object],[object Object]

Keys for Relationship Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

E-R Diagram with a Ternary Relationship

Cardinality Constraints on Ternary Relationship ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Binary Vs. Non-Binary Relationships ,[object Object],[object Object],[object Object],[object Object],[object Object]

Converting Non-Binary Relationships to Binary Form ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Converting Non-Binary Relationships (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object]

Design Issues ,[object Object],[object Object],[object Object],[object Object]

Weak Entity Sets ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Weak Entity Sets (Cont.) ,[object Object],[object Object],[object Object],[object Object]

Weak Entity Sets (Cont.) ,[object Object],[object Object]

More Weak Entity Set Examples ,[object Object],[object Object],[object Object],[object Object]

Specialization ,[object Object],[object Object],[object Object],[object Object]

Generalization ,[object Object],[object Object],[object Object]

Specialization and Generalization (Contd.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Design Constraints on a Specialization/Generalization ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Design Constraints on a Specialization/Generalization (Contd.) ,[object Object],[object Object],[object Object]

Aggregation ,[object Object],[object Object]

Aggregation (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

E-R Design Decisions ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

E-R Diagram for a Banking Enterprise

Summary of Symbols Used in E-R Notation

Reduction of an E-R Schema to Tables ,[object Object],[object Object],[object Object],[object Object],[object Object]

Representing Entity Sets as Tables ,[object Object]

Composite and Multivalued Attributes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Representing Weak Entity Sets ,[object Object]

Representing Relationship Sets as Tables ,[object Object],[object Object]

Redundancy of Tables ,[object Object],[object Object]

Redundancy of Tables (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object]

Representing Specialization as Tables ,[object Object],[object Object],[object Object],[object Object]

Representing Specialization as Tables (Cont.) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Relations Corresponding to Aggregation ,[object Object],[object Object],[object Object],[object Object]

Relations Corresponding to Aggregation (Cont.) ,[object Object],[object Object]

Existence Dependencies ,[object Object],[object Object],[object Object],If a loan entity is deleted, then all its associated payment entities must be deleted also. loan-payment payment loan

ER model

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ER model