Databases

Generalization

• In a generalization we form a new concept by emphasizing common aspects of existing concepts, leaving out special aspects

Generalization (cont.)

• Subclasses may overlap
• Subclasses may have multiple superclasses

Relationships Between Abstractions

Abstraction Concretization

classification exemplification

aggregation decomposition

generalization specialization

DATABASE TERMINOLOGY

• Data Models
• Keys and Identifiers
• Integrity and Consistency
• Triggers and Stored Procedures
• Null Values
• Normalization
• Surrogates - Things and Names

Data Model

• A data model consists of notations for expressing:
• data structures
• integrity constraints
• operations

Data Model - Data Structures

• All data models have notation for defining:
• attribute types
• entity types
• relationship types

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