System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-1 CHAPTER OVERVIEW  Entity Relationship Diagram  Data Model And Its Main Components  Relationship Model  Normalization  SQL Statements Practicals

System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-2 ENTITY RELATIONSHIP DIAGRAM ERD is network model that describes stored data of a system at a high level of abstraction. For system analyst, ERD has a major benefit: it highlights the relationship between data stores on DFD which would otherwise only be seen in the specification process.

System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-3 DATA MODEL AND ITS MAIN COMPONENTS A data model is a "description" of both a container for data and a methodology for storing and retrieving data from that container. Two steps to develop a data model: Defining Entity Types Defining Relationships

System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-4 RELATIONSHIP MODEL Relationship model defines a list of all the attributes to every table of entity of the data model. It is used a data modeling process sin order to test, improve and expand the constructed data model.

System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-5 NORMALISATION Normalisation is a process by which you identify and correct inherent problems and complexities in your record designs. The three types of normal forms comprise of:  First normal form  Second normal form  Third normal form. These three normal forms constitute a progression.

System Analysis and Design Copyright © Genetic Computer School 2007 SAD9-6 SQL STATEMENT PRACTICALS  SELECT statements  INSERT statements  SQL Functions  SQL Joins  SQL Aliases  SQL DDL Statements