Database Reference
In-Depth Information
5
Data Modeling with the
Entity-Relationship Model
●
To understand the two-phase data modeling/database
design process
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To understand the purpose of the data modeling process
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To understand entity-relationship (E-R) diagrams
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To be able to determine entities, attributes, and
relationships
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To be able to create entity identifiers
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To be able to determine minimum and maximum
cardinalities
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To understand variations of the E-R model
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To understand and be able to use ID-dependent and
other weak entities
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To understand and be able to use supertype/subtype
entities
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To understand and be able to use strong entity patterns
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To understand and be able to use the ID-dependent
association pattern
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To understand and be able to use the ID-dependent
multivalued attribute pattern
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To understand and be able to use the ID-dependent
archetype/instance pattern
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To understand and be able to use the line-item pattern
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To understand and be able to use the for-use-by
pattern
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To understand and be able to use recursive patterns
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To understand the iterative nature of the data modeling
process
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To be able to use the data modeling process
In this chapter
and the next, we consider
the design of databases that arise from the de-
velopment of new information systems. As you will
learn, such databases are designed by analyzing requirements
and creating a data model, or blueprint, of a database that will meet those
requirements. The data model is then transformed into a database design.
This chapter addresses the creation of data models using the entity-
relationship data model, the most popular modeling technique. This chapter
consists of three major sections. First, we explain the major elements of the
entity-relationship model and briefly describe several variations on that model.
Next, we examine a number of patterns in forms, reports, and data models that
you will encounter when data modeling. We then illustrate the data modeling
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