Question

这是我的数据库设计：

Person
------------------------------------------------
ID                UINT NOT NULL,
Name              VARCHAR(200) NOT NULL,
DOB               DATE NOT NULL,
Email             VARCHAR(100) NOT NULL


Person_History
------------------------------------------------
ID                UINT NOT NULL,
PersonID          UINT NOT NULL,
Name              VARCHAR(200) NOT NULL,
DOB               DATE NOT NULL,
Email             VARCHAR(100) NOT NULL
AuditID           UINT NOT NULL


Audit
------------------------------------------------
ID                UINT NOT NULL,
UserID            UINT NOT NULL,               -- Who
AffectedOn        DATE NOT NULL,               -- When
Comment           VARCHAR(500) NOT NULL        -- Why

我希望能够为人员历史记录类重用大部分人员代码，因为这些属性是重复的。按照现在的方式，我应该考虑并封装人员属性吗？这样，我可以使用合成，而不必在Person类和PersonHistory类之间复制代码？

Answer 1

我认为你应该避免重复你的数据库列，我认为它应该是：

Person
------------------------------------------------
ID                UINT NOT NULL,
Name              VARCHAR(200) NOT NULL,
DOB               DATE NOT NULL,
Email             VARCHAR(100) NOT NULL


Person_History
------------------------------------------------
ID                UINT NOT NULL,
PersonID          UINT NOT NULL,
AuditID           UINT NOT NULL


Audit
------------------------------------------------
ID                UINT NOT NULL,
UserID            UINT NOT NULL,               -- Who
AffectedOn        DATE NOT NULL,               -- When
Comment           VARCHAR(500) NOT NULL        -- Why

如果你正在使用JPA，你的类可以像这样映射：

@Entity
@Table(name = "PERSON")
public class Person {

@Id
@Column(name = "ID", unique = true, nullable = false)
private Integer id;

@Column(name = "DOB")
@Temporal(TemporalType.DATE)
private Date birthDate;

@Column(name = "EMAIL")
private String email;

@OneToMany(mappedBy="person", fetch=FetchType.LAZY, cascade=CascadeType.ALL)
private List<PersonHistory> personHistories;

// getters and setters...

}


@Entity
@Table(name = "PERSON_HISTORY")
public class PersonHistory {

@Id
@Column(name = "ID", unique = true, nullable = false)
private Integer id;

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="ID_PERSON", nullable=false)
private Person person;

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="ID_AUDIT", nullable=false)
private Audit audit;

// getters and setters...

}


@Entity
@Table(name = "AUDIT")
public class Audit {

@Id
@Column(name = "ID", unique = true, nullable = false)
private Integer id;

@Column(name = "AFFECTED_ON")
@Temporal(TemporalType.DATE)
private Date affectedOn;

@Column(name = "COMMENT")
private String comment;

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name="ID_USER", nullable=false)
private User user;

// getters and setters...

}

因此，在对象模型中，您将能够从人员历史记录中访问人员数据。

具有审计跟踪的领域模型的类设计

1 个答案: