Microsoft® Office Access Training Tools

Database design basics

Some database terms to know

Microsoft Office Access 2007 organizes your information into tables: lists of rows and columns reminiscent of an accountant’s pad or a Microsoft Office Excel 2007 worksheet. In a simple database, you might have only one table. For most databases you will need more than one. For example, you might have a table that stores information about products, another table that stores information about orders, and another table with information about customers.

Each row is also called a record, and each column, is also called a field. A record is a meaningful and consistent way to combine information about something. A field is a single item of information — an item type that appears in every record. In the Products table, for instance, each row or record would hold information about one product. Each column or field holds some type of information about that product, such as its name or price.

What is good database design?

Certain principles guide the database design process. The first principle is that duplicate information (also called redundant data) is bad, because it wastes space and increases the likelihood of errors and inconsistencies. The second principle is that the correctness and completeness of information is important. If your database contains incorrect information, any reports that pull information from the database will also contain incorrect information. As a result, any decisions you make that are based on those reports will then be misinformed.

A good database design is, therefore, one that:

• Divides your information into subject-based tables to reduce redundant data.
• Provides Access with the information it requires to join the information in the tables together as needed.
• Helps support and ensure the accuracy and integrity of your information.
• Accommodates your data processing and reporting needs.

The design process

The design process consists of the following steps:

• Determine the purpose of your database  

  This helps prepare you for the remaining steps.

• Find and organize the information required   

  Gather all of the types of information you might want to record in the database, such as product name and order number.

• Divide the information into tables  

  Divide your information items into major entities or subjects, such as Products or Orders. Each subject then becomes a table.

• Turn information items into columns  

  Decide what information you want to store in each table. Each item becomes a field, and is displayed as a column in the table. For example, an Employees table might include fields such as Last Name and Hire Date.

• Specify primary keys  

  Choose each table’s primary key. The primary key is a column that is used to uniquely identify each row. An example might be Product ID or Order ID.

• Set up the table relationships  

  Look at each table and decide how the data in one table is related to the data in other tables. Add fields to tables or create new tables to clarify the relationships, as necessary.

• Refine your design  

  Analyze your design for errors. Create the tables and add a few records of sample data. See if you can get the results you want from your tables. Make adjustments to the design, as needed.

• Apply the normalization rules  

  Apply the data normalization rules to see if your tables are structured correctly. Make adjustments to the tables, as needed.

More from this article  

Download: Database Basics - Microsoft Support Full Version (PDF)

Related Course Outlines

Microsoft Access 2003 Training Class Outlines:
Level 1 - Fundamentals
Level 2 - Intermediate
Level 3 - Advanced 1
Level 4 - Advanced 2
Levels 1 - 4 (PDF Document)

Microsoft Access 2007 Training Class Outlines:
Level 1 - Fundamentals
Level 2 - Intermediate
Level 3 - Advanced 1
Level 4 - Advanced 2
Levels 1 - 4 (PDF Document)