History of computingAbacus – Napier’s Bones – Slide Rule – Schickard’s Calculating Clock – Pascal’s calculator – Leibnitz Multiplier – Analytical Engine – Herman Hollerith Punch Card – John Von Neumann MachineConcepts of Number System: Binary (or Base 2) – Octal (or Base 8) – Decimal (or base 10) – Hexadecimal (or base 16)

INTRODUCTION TO DATA MODELLINGThe main effort during the system development life cycle (SDLC) was to produce a set of programs that automates a business process. Processing was the key driver for information systems, not the data or information. As the technology and complexity of the system grew, methodologies and modelling techniques were invented to improve the quality of the deliverables and to ensure that inexperienced programmers could follow repeatable SDLC processes.

TYPES OF DATA MODELLINGFlat Model: The flat Model (or Table) model consists of a single, two-dimensional array of data elements, where all members of a given column are assumed to be similar in values, and all members of the row are assumed to be related to one another.

Database packages are used to design a database in a computer. An example of a common database package is Microsoft Access. MS Access is a Relational Database Management System used to create and modify databases.

Editing data type in fieldsWhen creating tables, you should define the data types of the table to most closely match the type of data that will be entered in the field.To edit data type in Datasheet view. Click the field you wish to define. Click the Datasheet tab on the Ribbon. Click the down arrow next to the Data type. Choose the type of data that will be entered into the field.

Significance of Data ModelThe data model is a great communication tool because it facilitates interaction and communication between the designers, programmers and ends users. In essence, it does not allow one party’s bias towards a certain view of data (whether they consider it to be most important) to take hold.

A database management system is a collection of computer software that enables users to define, create and maintain a database. Defining a database involves specifying constraints for the data stored in the database, and normalization is a logical design method which minimizes duplicate, or redundant, data and design flaws. Normalization is the process of effectively organizing data in a database. The primary purpose of normalization is to allow the update, insert and delete operations to be performed on a single database table and propagated throughout the database by means of the defined relationship.

Types of Normal FormFirst Normal Form (1NF)First Normal Form (1NF) says that all column values must be atomic. 1NF dictates that for every row-by-column position in a given table, there exists only one value, not an array or list of values i.e in 1NF, the following rules are observed;

KEYA key is an attribute or field that can be used to identify a record in a database table or file.The Primary Key is a unique attribute that can be used to identify a record in a database table. For Example, in the student database table above, the attribute that is unique to identify each record is the Student ID or Reg No.

Entity-Relationship is a graphical representation of entities and their relationships with each other. Entity relationship diagrams (ERDs) illustrate the logical structure of a database. Diagrams created to design these entities and relationships are called entity-relationship diagrams or ER diagrams.