Spring Data JPA Query Method可以透過定義方法名稱來作為查詢的條件。當查詢或排序條件為@EmbeddedId複合主鍵(compound key)中的屬性時的命名方式如下。
例如EMPLOYEE資料表的主鍵為由本身的EMPLOYEE_ID及外鍵REGION_ID，DEPARTMENT_ID組成，則JPA的entiy類Employee設計如下。
Employee
@Entity
@Table(name="EMPLOYEE")
public class Employee {
@EmbeddedId
private EmployeePk id;
private String name;
private int age;
// getter and setter ommitted
}
EMPLOYEE的複合主鍵使用@EmbeddedId及一個@Embeddable類別EmployeePk來設定。
@Embeddable
public class EmployeePk implements Serializable {
private long employeeId;
private long departmentId;
private long regionId;
// getter and setter ommitted
}
在EmployeeRepository定義方法名稱時若查詢或排序條件包含了EmployeePk中的欄位，則命名方式如下。
public interface EmployeeRepository extends JpaRepository<Employee, EmployeePk> {
/**
* from
* EMPLOYEE
* where
* EMPLOYEE_ID = ?
* and DEPARTMENT_ID = ?
* and REGION_ID = ?
*/
List<Employee> findByIdAndAge(EmployeePk id, int age);
/**
* from
* EMPLOYEE
* where
* EMPLOYEE_ID = ?
* and NAME = ?
* order by
* DEPARTMENT_ID asc
*/
List<Employee> findByIdEmployeeIdAndNameOrderByIdDepartmentId(long employeeId, String name);
/**
* from
* EMPLOYEE
* where
* REGION_ID = ?
* AGE = ?
* order by
* REGION_ID asc,
* DEPARTMENT_ID asc,
* AGE desc
*/
List<Employee> findByIdRegionIdAndAgeOrderByIdRegionIdAscIdDepartmentIdAscAgeDesc(long regionId, int age);
}
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