使用枚举作为鉴别器值的SINGLE_TABLE继承策略 [英] SINGLE_TABLE inheritance strategy using enums as discriminator value
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问题描述
使用SINGLE_TABLE继承策略时可以使用枚举作为鉴别器值吗?
Is it possible to use an enum as a discriminator value when using SINGLE_TABLE inheritance strategy?
推荐答案
如果您正在尝试实现是不要重复鉴别器的值,有一个简单的解决方法。
If what you are trying to achieve is to not to duplicate the discriminator values, there is a simple workaround.
@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="FREQUENCY",
discriminatorType=DiscriminatorType.STRING
)
public abstract class Event {
}
@Entity
@DiscriminatorValue(value=Frequency.Values.WEEKLY)
public class WeeklyEvent extends Event {
…
}
public enum Frequency {
DAILY(Values.DAILY),
WEEKLY(Values.WEEKLY),
MONTHLY(Values.MONTHLY);
private String value;
…
public static class Values {
public static final String DAILY = "D";
public static final String WEEKLY = "W";
public static final String MONTHLY = "M";
}
}
不是超级优雅,而是比维持多个地方的价值。
Not super elegant, but better than having to maintain the values in multiple places.
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