Hi shweta,
You could do this by adding a function inside of Five and attaching it to the Do After Insert event on the FoodPurchase table.
Please use the link below to understand how to use a Do After Insert table event. Additionally the context provided to the function will have a new and old property which contains the data being inserted (Name, Price, Quantity) from your form.
For Example:
context.new.Name will have the name value from your form and as per the example below you can use Five’s executeQuery() function to add data to another table.
Table Event Issue (Do After Insert) - How do I? - Five Community Forums