Data Driven is an automation testing part in which test input or output values, these values are read from data files. It is performed when the values are changing by the time. The different data files may include data pools, csv files, Excel files. The data is then loaded into variables in recorded or manually coded scripts. For data driven testing we use Parameterzing and Regular expression Technique.
Ex: To evaluate login functionality, we use different user name and password combinations, variables are used to access different username and password. The list of username and password are stored in a data table or excel sheet.