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DATA & PROCESS MODELLING - Coggle Diagram
DATA & PROCESS MODELLING
Data Dictionary
A central storehouse of information about the system’s data so the analyst uses the data dictionary to collect, document, and organize specific facts about the system.
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Documenting the Data Elements:
- Data element name and label
- Alias
- Type and length
- Default value
- Source
- Security
- Responsible user(s)
- Description and comments
- Acceptable values
Documenting the Data Flows:
- Data flow name or label
- Description
- Alternate name(s)
- Origin
- Destination
- Record
- Volume and frequency
Documenting the Data Stores:
- Data store name or label
- Description
- Alternate name(s)
- Attributes
- Volume and frequency
Documenting the Processes:
- Process name or label
- Description
- Process number
- Process Description
Documenting the Entities:
- Entity name
- Description
- Alternate name(s)
- Input data flows
- Output data flows
Documenting the Records:
- Record or data structure name
- Definition or description
- Alternate name(s)
- Attributes
Process Description
Specifications
Structured English
- Resembles pseudocodes
- Describe the underlying business logic
Decision Table
Shows a logical structure, with all possible combinations of conditions and resulting actions
to ensure that you have overlooked nothing.
Types of tables:
- Tables with one condition
- Tables with two condition
- Tables with three condition
- Table with multiple outcomes
Decision Tree
A graphical representation of the conditions, actions, and rules found in a decision table.
Like flowcharts, decision trees are useful ways to present the system to management.
Decision trees and decision tables provide the same results, but in different forms.
Modular Design
Combinations of three logical structures or control structures which serve as building blocks for the process.
Logical structures:
- sequence
- selection
- iteration
LOGICAL & PHYSICAL MODEL
A physical model shows how the system’s requirements are implemented that can be used to develop physical models of an information system.
Sequence of Models
Systems analysts create a physical model of the current system and then develop a logical model of the current system before tackling a logical model of the new system.
Four-Model Approach
Develop a physical model of the current system, a logical model of the current system, a logical model of the new system, and a physical model of the new system
Data Flow Diagram (DFD)
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It shows how data moves through an information system but does not show program logic or processing steps.
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CONCEPTS
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A data flow diagram (DFD) uses various symbols to show how the system transforms input data into useful information.