210 likes | 235 Views
Learn how to model systems effectively before building or changing them using data flow diagrams. Explore software development cycles, identify problems, and understand user and technical requirements. Get insights on databases, CPU's, and operating systems. Develop a holistic view to streamline processes and meet organizational goals efficiently.
E N D
Data Flow Diagrams Introduction for organizers
The Problem • How to model a system before building or changing it
Build an Abstraction • Molecular Model
What Life Cycle? • What does it do? • All or Part? • Build or Buy? • Early decision for all software systems are whether to build or buy • WHO works on it? • WHO will run it? • HOW Long will it last?
Symbol of never-ending life The Software Development Cycle • Identify problems, opportunities and objectives. 9. Maintain the system 10. Evaluate and Plan for New Versions 8. Deploy 2. Define Information Requirements 7. Train 3. Analyze Detailed Needs 6. Install and Test 4. Specify or Design the Recommended System 5. Buy or Develop the Software
Different Points of View Databases CPU’s Operating Systems Winning Campaigns
Put the Parts Together Technology Organization’s Requirements User Experts Technical Experts
Who Does What? User Expert Technical Assistance Provider Joint Effort
Who Does What? User Expert Technical Assistance Provider Joint • Identify problems, opportunities and objectives. 9. Maintain the system 10. Evaluate and Plan for New Versions 8. Deploy 2. Define Information Requirements 7. Train 3. Analyze Detailed Needs 6. Install and Test 4. Specify or Design the Recommended System 5. Buy or Develop the Software
Data Flow Diagram Parts • External Entity • Process • Data Flow • Data Store
Funder Politician Allies General Population Constituency Government External Entity The External Entity symbol represents sources of data to the system or destinations of data from the system.
Signup Member Plan campaign Communicate message Pay Bills Process The Process symbol represents an activity that transforms or manipulates the data (combines, reorders, converts, etc.).
All Data Flows are defined in a data dictionary Data Flow The Data Flow symbol represents movement of data.
Data Store The Data Store symbol represents data that is not moving (delayed data at rest).
Procedure • Start at the top level with external entities to organization • Create a context diagram with system at center and external entities sending and receiving data flows;
Level 1 • CLO Example
Level 1 • CLO Example