Chapter 4. Querying a Database
In this chapter, we will cover the following recipes:
- Connecting to a database
 - Creating a DAO class
 - Calling a DAO method from a controller class
 - Saving an object
 - Retrieving an object
 - Retrieving a list of objects
 - Retrieving a list of objects with their dependencies
 - Updating an object
 - Deleting an object
 - Finding the number of results for an SQL query
 - Saving a list of objects at once
 - Reverting incomplete database modifications using transactions
 - Using Hibernate for powerful object persistence and querying