java - Hibernate 的 nullable = false 在所有情况下都不起作用

Question

我有以下类(class):

@Entity
@Table(name = "USERS")
public class User {

    private Long userID;

    @Id
    @Column(name = "userID")
    @GeneratedValue(generator = "increment")
    @GenericGenerator(name = "increment", strategy = "increment")
    public Long getUserID() {
        return userID;
    }

    @Column(nullable = false)
    private boolean isActive;

    @Column(nullable = false, unique = true)
    private String email;

    @Column(nullable = false)
    private String password;


    @Column
    @Temporal(TemporalType.TIMESTAMP)
    private Calendar lastLoggedIn;

    @Column(nullable = false)
    @Temporal(TemporalType.TIMESTAMP)
    private Calendar createdDate;

    @Version
    private Integer version;

    public String getEmail() {
        return email;
    }

    public boolean isActive() {
        return isActive;
    }

    public void setActive(boolean isActive) {
        this.isActive = isActive;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public Calendar getLastLoggedIn() {
        return lastLoggedIn;
    }

    public void setLastLoggedIn(Calendar lastLoggedIn) {
        this.lastLoggedIn = lastLoggedIn;
    }

    public Calendar getCreatedDate() {
        return createdDate;
    }

    public void setCreatedDate(Calendar createdDate) {
        this.createdDate = createdDate;
    }

    public Integer getVersion() {
        return version;
    }

    public void setVersion(Integer version) {
        this.version = version;
    }

    public void setUserID(Long userID) {
        this.userID = userID;
    }

    public User(Long userID, String email, String password, Calendar lastLoggedIn, Calendar createdDate, Integer version) {

    }

    // No argument constructor
    public User() {}
}

当我运行我的应用程序时，Hibernate 加载配置并为用户创建表。我正在使用 PostgreSQL。这是正在生成的 SQL 语句(由 hibernate 记录):

Hibernate: create table USERS 
           (userID int8 not null, active boolean not null, createdDate timestamp, 
            email varchar(255), lastLoggedIn timestamp, 
            password varchar(255), version int4, primary key (userID))

为什么 boolean 值被创建为非空值而字符串/时间戳不是？如果您尝试插入没有电子邮件或密码的用户，我不会有异常(exception)，但使用这个生成的模式它不会。还有另一种方法可以强制 Hibernate 将字段创建为不可空吗？

Answer 1

来自 5.1.4.1.2. Access type :

By default the access type of a class hierarchy is defined by the position of the @Id or @EmbeddedId annotations. If these annotations are on a field, then only fields are considered for persistence and the state is accessed via the field. If there annotations are on a getter, then only the getters are considered for persistence and the state is accessed via the getter/setter.

当您在 getter 上注释 @Id 时，您正在使用属性访问。因此，hibernate 将忽略字段上标记的所有映射注释，只使用 getter 上的注释来生成 DDL。因为 getter 上没有注解，所以使用默认设置。

如果您更改为在 userID 上注释 @Id 而不是 getUserID()

，您应该会得到想要的结果