Transcript Database Design Using the REA Data Model

Database Design Using the REA
Data Model
Chapter 17
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Learning Objectives
• Discuss the steps for designing and
implementing a database system.
• Use the REA data model to design an AIS
database.
• Draw an REA diagram of an AIS database.
• Read an REA diagram and explain what it
reveals about the business activities and policies
of the organization being modeled.
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Database Design Process
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Data Modeling
• Process of defining a database so that it
faithfully represents all aspects of the
organization, including its interactions with the
external environment.
▫ Entity-relationship (E-R) diagrams
▫ REA data model
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REA Modeling
• Resources
▫ Things that have economic value to the
organization (e.g., inventory, cash)
• Events
▫ Various business activities that management
wants to collect information on
• Agents
▫ People and organizations that participate in events
(both internal (e.g., employees) and external (e.g.,
customers/vendors) to the organization)
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REA Basic Template
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Creating an REA Model
• Identify relevant events
▫ Give-get exchange (economic duality)
• Identify resources and agents
▫ Resource reduced in give event
▫ Resource acquired in get event
• Determine cardinalities of relationships
▫ Nature of the relationship between the two
entities
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Cardinality Notation Methods
• Graphical symbols
▫ Graphical symbols represent minimum–
maximum cardinalities
• (Min, Max) notation
▫ Pairs representing the minimum–maximum
cardinalities
• UML notation
▫ Pairs representing the minimum–maximum
cardinalities
• Maximums only (Microsoft Access)
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Key Terms
• Data modeling
• Entity-relationship (E-R)
diagram
• REA data model
• Resources
• Events
• Agents
• Cardinalities
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Minimum cardinality
Maximum cardinality
One-to-One (1:1) relationship
One-to-Many (1:N)
relationship
• Many-Many (M:N)
relationship
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