Boundary Value Analysis is a test case design technique, if there is lot of input text boxes and dropdown boxes then will use Boundary Value analysis technique to simplify the test design.
By using Boundary Value Analysis technique testers will create test cases for the data input required fields. For example there is one Name text box which allows maximum 30 characters. So in this case writing test cases by entering each character once will be very difficult so then will choose boundary value analysis.
So in this case at max 5 test cases will come:
Test case1: minimum -1 character: Validating not entering anything in text box
Test case2: minimum +1 character: Validating with only one char
Test case3: maximum -1 character: Validating with 29 chars
Test case4: minimum +1 character: Validating with 31 charactersTest case1: any one middle number: validating with 15 chars
Another Case: If there is any drop-down box with the 30 lists then also will follow the same conditions