Implementing an EJB 3.0 Dynamic Query

Using EntityManager methods createQuery and createNativeQuery(String sqlString, Class resultType), you can create a Query object dynamically at runtime (see "Using Java").

Using the Query methods getResultList, getSingleResult, or executeUpdate you can execute the query (see "Executing a Query").

For more information, see:

• "Acquiring an EntityManager"

• "Creating a Dynamic EJB QL Query with the Entity Manager"

• "Creating a Dynamic TopLink Expression Query with the EntityManager"

• "Creating a Dynamic Native SQL Query with the EntityManager"

• "Configuring Query Hints"

• "Executing a Query"

Query queryEmployees = entityManager.createQuery(
    "SELECT OBJECT(emp) FROM Employee emp WHERE emp.firstName = :firstname"
);

queryEmployeeByFirstName.setParameter("firstName", "Joan");

Collection employees = queryEmployees.getResultList();