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11 Cards in this Set
- Front
- Back
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Five steps in database design
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1) system analysis: initial planning to determine the need for and feasibility of developing a new system
2) conceptual design: developing different schemas for the new system at the conceptual, external and internal levels 3) physical design: translating the internal-level schema into the actual database structures 4) implementation and conversion: activities associated with transferring data from existing system to the new database 5) using and maintaining the new system: monitoring system performance and user satisfaction |
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data modeling
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the process of defining a database so that it faithfully represents all aspects of the organization, including its interactions with the external environment; occurs in stage one and two (system analysis and conceptual design)
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entity-relationship (E-R) diagram
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a graphical technique for portraying a database schema; shows the various entities being modeled and the important relationship among them
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entity
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anything about which the organization want to collect and store information
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REA data model
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developed specifically for use in designing AIS, focuses on the business semantics underlying an organization's value-chain activities
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resources
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have economic value ex: cash and inventory
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events
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various business activities about which management wants to collect information for planning or control purposes ex: sales and receive cash
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agents
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people and organizations that participate in events ex: employees and customers
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cardinalities
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describe the nature of he relationship between two entities by indicating how many instances of one entity can be linked to each specific instance of another entity
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price and cost data
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general rule is that time-independent data should be stored as an attribute of a resource or agent, but data that varies across time should be stored with event entities or M:N relationship that link a resource and an event
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concatenated keys
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multiple-attribute primary keys
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