Designing Automation framework for testing web application

Page Object Model

It will give you way to manage and maintain your code. Now it's upto you if you want to divide your validation or function test separately using same.

For Excel file, you just need to create few classes which have the business logic to read and set the data in excel file. You can do it similarly we have done in KeyDriven framework just the difference is here you will call them when ever you need it.

Below is the reference for POM.

http://www.toolsqa.com/selenium-webdriver/page-object-model/

You could start designing your framework around the Test harness concept. Split your code into three major concerns(SoC):

• Execution engine - a core Selenium functionality that know only how to execute commands
• Tests
  • Cucumber *.feature files, containing the test flow
  • TestNG engine that will support your Step definitions
• Specification - keeps only the environment, site and browser specifics

This model will give you a scalable and easy to maintain test framework.

the architecture have the ability to execute the scripts in batch

All this will require a CI server to help you manage the QA process:

• Jenkins (and Database plugin for your case)
• Bamboo
• Hudson

are the most used ones to do that.

there would also be data that i need to pass at runtime using excel

Data-driven testing is the approach that will help you achieve this. Here is an example with TestNG. It would be nice to organize this functionality as a separate TestDataLibrary package in your project.

Validation: UI Validations, backend(database) validation

Selenium team do suggest such DB validation, skipping the Application layer. But keep in mind that not all requirements actually need to be tested via the UI. Most of the times - the integration tests can do the same job just fine. Some even advice to keep only the E2E on the presentation layer.