2个属性中的一个应为null（EntityFramework Code First） [英] One out of 2 properties should be null (EntityFramework Code First)

问题描述

我在论坛中搜索了很多，但没有发现有关此问题的任何内容。

I've searched a lot in the forum, but haven't found anything about regarding this issue.

我在EntityFramework代码中有2个属性首先： / p>

I have 2 properties in the EntityFramework Code First:

    [Column(TypeName = "Money")]
    public decimal? Debit { get; set; }
    [Column(TypeName = "Money")]
    public decimal? Credit { get; set; }

其中一个应该不为空，但另一个应为null
示例：

One of them should be not null, but the other one should be null Examples:

Debit=null;
Credit=34;

Debit=45;
Credit=null;

另一方面，不可能同时设置两者，也不能设置为空。
可以用数据注释处理这个问题，还是应该用解决方法解决？

On the other hand, it should not be possible to set both or none of them null. Is it possible to handle this issue with data annotations or should I solve it with a workaround?

最好的问候！

推荐答案

您可以随时对数据库端进行验证，具有约束条件，

You could always do the validation on the database side with a constraint,

ALTER TABLE TableName 
    ADD CONSTRAINT OneColumnNull CHECK 
    ((Debit IS NULL AND Credit IS NOT NULL) OR 
     (Debit IS NOT NULL AND Credit IS NULL)
    )

完全符合您的要求。您可以将该查询作为数据库迁移脚本之一。

does exactly what you are looking for. You could just put that query as part of one of your database migration scripts.

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