Question

我在两个不同的表中有两个不同的枚举（它们具有相同的结构，但含义不同）。

这是我从FIRST_SCHEMA开始的第一个表，叫做TYPE

id   team   desc              days
1    "AB"   "Do Thins"        2
2    "CD"   "Other things"    3

这是SECOND_SCHEMA中的第二个类型，称为TYPE。

id   team   desc                       days
1    "AB"   "Other other thins"        1
2    "CD"   "More and more things"     1

我尝试使用休眠注释在Java中映射此枚举，它们就像这样：

FirstEnum.java

@Entity
@Table(name = "TYPE", schema="FIRST_SCHEMA")
public enum FirstEnum implements SuperEnum<FirstEnum> {

    DO_THINGS(1, "AB", "Do things", 2),
    OTHER_THINGS(2, "CD", "Other things", 3);


    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private final int value;

    @Column(name = "team")
    private final String team;

    @Column(name = "desc")
    private final String dec;

    @Column(name = "days")
    private final int days;

    //getters and setters
}

SecondEnum.java

@Entity
@Table(name = "TYPE", schema="SECOND_SCHEMA")
public enum SecondEnum implements SuperEnum<SecondEnum> {

    DO_THINGS(1, "AB", "Other other thins", 2),
    OTHER_THINGS(2, "CD", "More and more thingsS", 3);


    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private final int value;

    @Column(name = "team")
    private final String team;

    @Column(name = "desc")
    private final String dec;

    @Column(name = "days")
    private final int days;

    //getters and setters
}

使用这些类型之一的类的映射如下：

Foo.java

@Table(name = "TABLE", schema="FIRST_SCHEMA")
@Entity
public class Foo extends Bar implements Serializable {
    private static final long serialVersionUID = 1L;


    @Enumerated(EnumType.ORDINAL)
    @Column(name = "id_type")
    private FirstEnum type;

    //getters and setters
}

如果我在persistence.xml中设置以下行：

<property name="hibernate.hbm2ddl.auto" value="update" />

到

<property name="hibernate.hbm2ddl.auto" value="none" />

它可以按预期工作，不会创建新的“类型”表。但是，如果没有，即使您已经拥有类型表，它也会创建一个空表。

我映射错了什么？

Answer 1

首先，枚举用于常量值.. 如果这样放在表里，还不如直接创建一个类..

@Entity 
@Data 
@Accessors(chain = true) 
public class FirstEnum {


    @Id
    @NotNull
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int value;

    @Column(name = "team")
    private String team;

    @Column(name = "desc")
    private String dec;

    @Column(name = "days")
    private int days;

}

枚举功能用于在您的类中具有恒定的业务逻辑。所以也许你可以在没有数据库的情况下定义枚举..

public enum SecondEnum {

    DO_THINGS(1, "AB", "Other other thins", 2),
    OTHER_THINGS(2, "CD", "More and more thingsS", 3);
}

Hibernate不断为我的枚举创建表

1 个答案: