Mastering the Three Fundamental Steps in Relational Database Modeling Using ERD and UML techniques

A relational database is the most widely used type of database by many organizations for storing structured data which are organized into rows and columns in a table efficiently, and retrieving various information contained therein effortlessly.
Creating a relational database requires a top-down approach. This top-down approach is made up of three main steps which are, (i) conceptual data modeling, (ii) logical data modeling, and (iii) physical data modeling. Conceptual data modeling is the process of identifying all the ‘entities’ involved in a given information system, the ‘attributes’ of those entities, and the relationships between the entities. The Entity Relationship Diagram (ERD) and the Unified Modeling Language (UML) are the two principal techniques used in Conceptual data modeling. A system analyst (or software engineer) can make use of any or both techniques. This book covered both techniques. Logical data modeling is the process of converting an ERD to a relational database whereby an entity is converted to a table , an attribute of an entity is converted to a column name in the table, a key attribute of an entity is converted to a primary key in the table, and the relationship between any two entities is established through the use of foreign key between the two tables, etc. Physical data modeling is the process of converting a relational database into actual storage on a computer. This can be achieved by writing appropriate SQL commands for storing the relational database on a relational database server such as Oracle, MySQL, Microsoft SQL server, etc., and then querying the server for various information that can be retrieved from it. This book is organized into seven chapters. Chapter 1 is the Introduction . It gives an overview of the three basic steps involved in relational database modeling. Chapter 2 delved extensively on the “fundamentals of a relational database modeling”. It provides the reader with the basic concepts involved in a relational database; such concepts include: table (entity), column (attribute), row (tuple), primary key, foreign key, Relational Database Management System (RDMS), etc. Chapter 3 focused on “Conceptual Data Modeling using ERD”. This is the first top-down approach in relational database modeling. The chapter contained many sections and sub-sections that explained vividly how to model a system using ERD as well as how to decompose any many-to-many relationship that exists in an ERD”. Chapter 4 elaborated on “Logical Data Modeling”. This is the second top-down approach in relational database modeling. The chapter showed how to convert an ERD diagram to a relational database as well as Normalizing the tables. Chapter 5 discussed on “Physical Data Modeling”. This is the third and last top-down approach in relational database modeling. A practical example on how to transform a relational database to physical data on a computer using SQL commands was well illustrated in the chapter. Chapter 6 explained in detail how to model a system using UML diagrams, while Chapter 7 shows how to transform a ‘system model’ to a ‘system design’.