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隨着使用下面的代碼使用@EmbeddedId和@MapsId原因NULL插入(違反NOT NULL約束)
@Embeddable
public class EmployeeId implements Serializable {
@Column(name = "company_id")
private Long companyId;
@Column(name = "employee_id")
private Long employeeNumber;
}
@Entity
public class Employee {
@EmbeddedId
private EmployeeId id;
private String name;
@MapsId("name=companyId")
@ManyToOne
@JoinColumn(name = "company_id")
private Company company;
}
當試圖持續存在或合併Employee
實體,我們可以看到,作爲嘗試了NULL
是插入到company_id字段中。
如何避免插入NULL
?