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Transitioning from IDEF0 to IDEF1: Understanding Information Structures and Models

This comprehensive guide explores the transition from IDEF0 to IDEF1 in systems analysis. It emphasizes the importance of defining information structures through various models, such as entity-relationship models and fully attributed models. It covers essential concepts including entities, attributes, and relationships, while illustrating practical examples like lecturers and students. Additionally, the document outlines guidelines for creating activity diagrams, establishing relationships, and resolving complex many-to-many links in data modeling, providing a robust framework for improving data structure management.

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Transitioning from IDEF0 to IDEF1: Understanding Information Structures and Models

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  1. Systems Analysis IDEF0 and IDEF1.x

  2. Systems Analysis • Moving from IDEF0 to IDEF1.x • Technique for describing information structures • Information models represent: • things - entities • properties of things - attributes • associations between things - relationships

  3. A Entities • Abstractions of real world things • eg CUSTOMER • does not relate to specifict customers • ...any distinguishable person, place, thing, event or concept about which information is kept. (Bruce 1992) Specific customer

  4. A A A Attributes • Each set of data for an entity may be regarded as an ‘instance’ of that entitiy • The individual pieces of data for an instance are called attributes Name Address Tel No. Credit history Customer

  5. Relationships • Imagine two entities: Lecturer and Student • Lecturers teach students • Teaching is the “relationship” between the two abstract entities

  6. Types of Information Model • Entity Relationship Model: shows major entities and relationships - wide business area • Key Based Models: Third normal form model that describes major data structures (entities, keys and sample attributes) - wide business area

  7. Types of Information Model • Project Information Model: describes a portion of an overall data structure - specific to a development project • Fully Attributed Model: third (or higher) normal form model (entities, attributes, relationships and integrity rules) - single project

  8. Entity Name Primary Key Area Data Area IDEF1.x - Components • Entity • Entity Names are instances - each instance represents a customer not multiple customers • Area above line is for key attributes • Area below line if for non-key attributes

  9. Relationships • Relationships are connections or links between entities LECTURER STUDENT teaches One to Many

  10. Relationships • Non-identifying Relationship LECTURER STUDENT teaches lecturer-no student-no lecturer-no (FK)

  11. Relationships • Identifying Relationship BOOK-COPY BOOK copy-no classmark (FK) classmark

  12. Relationships • Resolving many to many links • A person may use more than one address, an address may be used by more than one person PERSON ADDRESS person-id address-id may use used by ADDRESS-USAGE person-id (FK) address-id (FK) usage-type

  13. Cardinality Identifying Relationship Non-identifying Relationship One to Zero or more P P One to One or more Z Z One to Zero or One N N One to exactly N

  14. Cardinality • Example - Zero or One to One or more relationship SALESPERSON salesperson-id receives credit for P ORDER order-no salesperson-id (FK)

  15. Generating IDEF1.x Activity Model Worksheet Pack Receive Purchase Request Buying Knowledge Completed Worksheet Pack Establish Supplier Quotes WORKSHEET-PACKAGE QUOTES Information model

  16. Information model QUOTES DRAWINGS LAYOUTS OPERATIONS WORKSHEET

  17. Guidelines • Create activity dia of business process • From the info flows, create entity pool • Create entities on information model • Investigate detail of aggregate entities • Draw relationships between entities • Resolve many-to-many links • Insert keys and specify identifying/non-identifying relationships • Validate with users

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