Chapter 5. Querying Entities using JPQL and the Criteria API
In this chapter, we will cover:
- Populating the Patient and Medication tables
- Using the Select clause
- Using the Where clause
- Controlling the number of entities returned by a select query
- Using the Delete query
- Using the Update query
- Using parameters in a query
- Using a named query
- Using the Criteria API
There are two primary Java EE technologies for querying a database: Java Persistence Query Language (JPQL) and the Criteria API. JPQL is similar in appearance and usage to SQL while the Criteria API provides a more type-safe and object-oriented entity querying capability.
When using EJB 2.0, developers used EJB QL as the query language. With the introduction of J2EE 5.0, JPQL was introduced ...