Creating a Conceptual Model

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Creating a Conceptual Model
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Overview

• Conceptual models illustrate concepts in a
  domain.
• Library, Book, Loan.
• We explore
• When.
• Notation.
• Guidelines.
• Practice.

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Objectives

• Read and create conceptual models.
• Apply principles for the identification of
  concepts, attributes, and associations.
• Add appropriate attributes and associations.

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A Partial Sample Process
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Modeling Concepts in a Domain

• Object modeling might support a reduced
  semantic gap in models at different stages.
• But an exact 1-1 mapping is not always present
  or desirable.

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Conceptual Models

• Conceptual models represent ideas, things, and
  objects in the real-world problem domain.
• A concept is a set of examples of like things.
• Example All library patrons.

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Not A Diagram of Software Components

• A conceptual model is not a picture of
• Software components.
• Classes in an object-oriented programming
  language.
• It illustrates real-world concepts.

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Identifying Concepts in the Domain

• Create a list of candidate concepts from this
  common concepts list.

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Identifying Concepts in the Domain
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Identifying Concepts

• At least three strategies
• Use the common concepts list.
• Identify nouns and noun phrases.
• Abbot Analysis.
• Study and apply models from others.
• Example Analysis Patterns, Fowler,
  Prentice-Hall, 1996.

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Initial Conceptual Model
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Optional Exercise

• As far as possible, name and draw influence
  lines between artifacts. (when done, see
  artifact names on last page of this module).

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The Spirit of Conceptual Modeling The Map Maker

• Make a class model in the spirit of how a
  map-maker works.
• A conceptual model is a map of concepts in a
  domain.
• Use the familiar names of the territory.
• Do not add things that are not there.
• Exclude information from a map if not
  relevant to the purpose of the map.

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Dimensions of Decomposition

• Conceptual modeling emphasizes decomposition by
  things.

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Exercises

• Begin creating a conceptual model for the first
  development cycle of the course project.
• Start by listing candidate concepts, using the
  common concepts list.

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Associations

• Are noteworthy relationships between concepts.
• Are bidirectional.
• Should have a meaningful name.
• form ltNoungt ltVerb-phrasegt ltNoungt

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Multiplicity
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Roles

• Each end of an association is a role having
• Multiplicity.
• An optional name.

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Identifying Important Associations

• When show? If memory of relationship needs to
  be preserved for some duration.
• Common association categories.

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Identifying Important Associations
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Reading Direction Arrow

• An association can have an optional reading
  direction arrow.
• Aids in reading only.
• Has no semantic meaning.

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Conceptual Model Example
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Exercise

• Add associations to the conceptual model.

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Attributes

• Only simple attributes.
• Examples number, string, boolean, date, time.
• No foreign keys.

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Attributes

• Relate concepts with an association, not an
  attribute.
• Add attributes to fulfill the information needs
  of the requirements.

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Sample Attributes
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Exercise

• Add attributes to the conceptual model

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What We Learned Reflection

• Conceptual model Concepts in a problem domain.
• Guidelines for showing concepts, associations,
  and attributes.
• Reflection.
• How might you use this at work?
• Relationship to other artifacts?

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Skill and Objectives Evaluation
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Reference Sample Artifacts