how to update a table in spring data JPA using where clause

Question

I want to update particular record in a table and i am using primary key(empId) and one more column(empSalary) to identify the particular column. As we know primary key(empId) is enough to identify the record. But in my case i want update the record if that employee salary is 1000. is there any option to update a record using entity not query?. I am using spring data JPA

Example:

public class Employee {

    @Id
    @Column
    private int empId;

    @Column
    private String name;

    @Column
    private float salary;

    @Column
    private String state;

    // getters, setters
}

I want to update the whole table if empId and salary match with table.

Answer 1

In an EmployeeRepository create the following method;

findOneByEmpIdAndSalary(Integer empId, Float salary);

Then you can pass the salary = 1000.0 or can create a default method within the same repository with that value hard coded;

public interface EmployeeRepository extends JpaRepository<Employee, Integer> {

    Optional<Employee> findOneByEmpIdAndSalary(Integer empId, Float salary);

    default Optional<Employee> findOneByEmpIdAndSalaryEqualTo1000(Integer empId) {
        return findOneByEmpIdAndSalary(empId, 1000.0);
    }
}

I used findOne since you are already selecting with the primary key plus an extra condition, so you will either get one or none, thus using Optional<T> as the result, to control either possibility in a better way.

After fetching this entity within a @Transactional state, just update the resulting entity. If Optional is not empty, then the ending of the transaction will commit that update to the DB, else nothing.

@Transactional
public String updateWithCondition(Integer empId) {
    employeeRepository.findOneByEmpIdAndSalaryEqualTo1000(empId)
            .ifPresent(employee -> employee.setState("desired Update"));
}

Like the above snippet as an example.

Answer 2

You can use @Modifying along with @Query annotation to include where clause in your query. This way you save a round trip to DB by fetching the entity first and then updating it.

This article from Baeldung explains it neatly. Hope it helps.