110 likes | 231 Views
CS E 4 4 1: Systems Analysis & Design. Basic CASE Models of Visible Analyst Lab2 Yusuf Altunel. The Basic CASE Models. Functional Decomposition Model (FDM) - Business Model Entity Relationship Model (ERM) - Data Model Object Model (OCM) - Object Class Model Process Model (DFD)
E N D
CSE 441: Systems Analysis & Design Basic CASE Models of Visible Analyst Lab2 Yusuf Altunel
The Basic CASE Models • Functional Decomposition Model (FDM) - Business Model • Entity Relationship Model (ERM) - Data Model • Object Model (OCM) - Object Class Model • Process Model (DFD) - Data Flow Diagram
StructuredModellingTechniques • Large systems can be partitioned for furtheranalysis • into component subsystems • or sub-functions. • Specifications for individual components • are easier and faster • than to definethan the total system. • The interaction between the parts • can be planned, designed and implemented • to reflect improved information flows and controls. • More than one person • can work with the same system in the network edition. OVERVIEW
ENTITY RELATIONSHIP MODELING • Entity Relationship Modeling or Data Modeling • The technique used by Visible Analyst • for representing data. • The purpose ofthis technique is • to graphically demonstrate • how entities are related to one another. • An entity could be • Customer, Product, Inventory, Supplier, Sale, • or some other label generally in the form of a singular noun.
ERD • ERD (Entity Relationship Diagram) • The diagramming technique • used for Data Modelling • Relationships between entities • are described in terms of their CARDINALITY - one-to-one - one-to-many - many-to-many
Relationship cardinality ratio • Think up an example of a 1:1 relationship? • 1:1 • Think up an example of a 1:M relationship? • 1:M • How about a M:M relationship? • M:M A department has 1 manager A studenttakescourses Customers buying products
DFD (Data Flow Diagram) • The diagramming technique used • for PROCESSMODELLING • The DFD consists of • data flows, • processes, • data stores, • external entities. • Methodologies used for Process Modeling: -Yourdon/DeMarco -Gane & Sarson -SSADM - Metrica. • Visible Analyst implements thesetechniques.