Testing Databases
Objectives
This lesson covers the following objectives:
- Develop and apply a strategy for testing that a database functions as designed
Purpose
- Most people, when they buy a car, wish to know that it is reliable and will not break down.
- So the manufacturers will put the car through a number of tests before it is available to be sold.
- The same is true of a database; before it is sold to a customer, it is tested to verify that it meets the business requirements.
Unit Testing
- If two things are tested at once and the test fails, it is difficult or impossible to work out what has caused the failure.
- So it is important to test only one thing at a time.
- This is commonly referred to as unit testing.
What Could Be Tested?
- When testing a database, a variety of things need to be tested.
- For example:
- Columns should be tested that they contain the correct data type.
- Columns should be tested that they can accommodate the largest amount of data that might be entered.
- Constraints should be checked that they only constrain or limit data that they are supposed to—no more and no less.
What Should Be Tested?
- It is frequently unrealistic to test every column and every constraint in every table in a database if it is a large database.
- A random spread of tests, that check some columns and some constraints, should be carried out.
Designing Tests
- Before you carry out a test, you should have a good idea of what result you expect to see if the database is
- working as expected.
- This should be documented before you carry out the test in a table similar to the one shown:

Running Tests
- Once you have designed your test, you can run it and record your results.
Terminology
Key terms used in this lesson included:
- Testing
- Unit Testing
Summary
In this lesson, you should have learned how to:
- Develop and apply a strategy for testing that a database functions as designed
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