Lesson 1

This course describes a design methodology for creating a database capable of producing useful information in a consistent manner. Current relational database software has brought point-and-click ease to the task of creating dabases.
However, unless your database is properly designed, it will be characterized by data problems such as

1. missing data,
2. incorrect data and
3. mismatched data

that will make it almost useless, no matter how user-friendly the software is.

This course on Relational Database Design is the first step in learning a design methodology that will help you create a database capable of producing useful information in a consistent manner. Specifically, I will discuss the principles of data modeling, culminating in the creation of a database diagram.

After completing the first course in this series, you will be able to:

1. Explain relational database design concepts and terminology
2. Explain the difference between conceptual and physical models
3. Develop a conceptual design
4. Analyze user information requirements
5. Describe the entity/relationship modeling approach
6. Identify entities
7. Model relationships and identify attributes
8. Use primary and foreign keys

A database is a collection of information related information and preferably organized. A database consists of the physical files you set up on a computer when installing the database software. On the other hand, a database model is more of a concept than a physical object and is used to create the tables in your database. By definition, a database is a structured object. It can be a pile of papers, but most likely in the modern world it exists on a computer system. The structured object consists of data and metadata, with metadata being the structured part. Data in a database is the actual stored descriptive information, such as all the names and addresses of your customers. Metadata describes the structure applied by the database to the customer data. In other words, the metadata is the customer table definition. The customer table definition contains the fields for the names and addresses, the lengths of each of those fields, and datatypes. A datatype restricts values in fields, such as allowing only a date, or a number. Metadata applies structure and organization to raw data. A database is often represented graphically by a cylindrical disk where the database contains both metadata and raw data. The physical implementation of the database itself is stored and executed on a database server computer.

In this course, I will discuss relational database design with the aid of two kinds of graphical displays,

1. the SlideShow and
2. the MouseOver.

You will complete a course project that involves creating a database design diagram appropriate to the needs of Stories on CD, Inc. This is a fictional company that sells books on CD via mail order. You will complete the project incrementally via a series of exercises that provide opportunities to apply what you have learned to a real-world situation. While the company is small and its needs are relatively simple, the principles you apply to analyzing its requirements and designing a database to meet them are the same as those that database designers apply to much larger projects involving multi-national corporations.

Data Modeling and Relational Database Design is the first of two courses in the Relational Database Design Fundamentals series.The second course in the series discusses Data Analysis and Normalization The next lesson outlines the prerequisites for this course.