Tutorial 4 Data Modeling and Data Dictionary

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Tutorial 4 Data Modeling and Data Dictionary

• SEG3430 Systems Analysis and Design

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Data Models

• A collection of conceptual and abstract tools
  (non-physical), for describing
• Data
• (Entities)
• Data Relationships
• (Relationships)
• Data Semantics
• (Meaning Instance)
• Consistency constraint
• (Cardinality Modality)

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Data Models

• Data Model Classification
• Logical data model
• Abstract and high level description of data and
  their relationships
• Physical data model
• Concern more about the implementation of the data
  model using tools like database, files, networks,
  systems

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This tutorial?

• Entity Relationship Model (ER-Model)
• An example of ER-Model

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ER-Model

• Three major elements in ER-Model
• Entity
• Attributes
• Relationships

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ER-Model

• Entities
• A person, place or thing about which the data is
  collected (According to lecture notes)
• A class of objects
• Difference between entities and instances
• Entities Multiple occurrence of objects
• Instances A particular example of entities

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ER-Model

• Entities

A person, place or thing about Which the data is
collected. In This case, it is the entity
of student
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ER-Model

• Attributes

• Type of information that
• is captured related to the entity.
• For the student entity, some related
• attributes include the
• Student ID
• Student Name
• Which year of study
• Which department the student
• studies in?
• 5. College information

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ER-Model

• Relationships
• The associations and connections between the
  entities.
• Depending on the cardinality and modality, a
  number of relationship symbols are introduced.

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ER-Model

• Relationship
• Exactly one relationship (1)

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ER-Model

• Zero or 1 relationship
• (0/1)

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ER-Model

• One or more relationship ( gt 1)

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ER-Model

• Zero or more relationship ( gt 0)

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ER-Model

• More than one (gt1)

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An example of ER-Model

• Consider the following example
• The bank is organized into branches. Each branch
  is located in a particular city and is identified
  by a unique id
• Bank customers are identified by their
  customer-id values. The bank stores the address
  of each customer. Each customer is assigned to
  one bank to take care of.

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An example of ER-Model

• The bank offers two types of accounts saving
  and loan accounts. Each account can be held by
  more than one customer, and a customer can have
  more than one account. Each account is assigned a
  unique account number. The bank maintains a
  record of each accounts balance. Each account
  has different interest rate.

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An example of ER-Model

• For each loan, the bank keeps track of the
  payments. A payment number identifies a
  particular payment. The date and amount are
  recorded for each payment.

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End of this tutorial

• Thank you