I have gone through the examples of writing the grid data to database. First, we are inserting into the store and then store.sync is making a proxy call to write into the database etc.
I have a requirement to validate the entered data in the grid for addition of new values or editing the values against the database to check whether already such values exists. If such value already exist, then it should prompt a message returned from the server saying such value already exists in the database to the user and ask him to either change the entered values or cancel the existing entry.
How to acheive the above stated functionality.