what is Data-driven, Time-Driven and keyword-driven testing

[B]Data-Driven Testing:[/B]
The reexecution of automation test script with multiple test data in multiple times is called DDT.
First test engineers are preparing test script for sample input and then execute test script for valid and invalid inputs.

We can use this testing by 4 ways
[B]1. Keyword - Driven testing : [/B]During this way we are entering the input values dynamically through keyboard.

[B]2. Through flat files: [/B]Here Test script is reading values from flat files(flat files means note pad files which consists of input values)

[B]3. Through data table :[/B] Script is reading values from xl sheet/datatable.to fill that xlsheet we are concentrating on to connect database and genrate our own values.

[B]4. From front end object:[/B] Some times TEs are coducting DDT depending on multiple data objects such as list boxes, menu, active x controls, table grids and data windows