在没有OrderBy的情况下从Entity Framework数据库中选择随机记录 [英] Picking random record from Entity Framework database without OrderBy

问题描述

我尝试从数据库中获取随机记录:

I try to get random record from database:

 personToCall = db.Persons.Skip(toSkip).Take(1).First();

但我收到异常消息，告诉我:

but I get exception which tells me:

{"The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'."}

我可以在没有 OrderBy 的情况下这样做吗?对数据结构(O(nlogn))进行排序以选择随机元素(应为常数)看起来并不明智.

Can I do it without OrderBy? Sorting data structure (O(nlogn)) to pick random element(which should be constant) doesn't look wise.

编辑:我使用的是Entity Framework 6.1.1.

I use Entity Framework 6.1.1.

推荐答案

您可以输入类似以下内容:

You can have something like :

personToCall = db.Persons.OrderBy(r => Guid.NewGuid()).Skip(toSkip).Take(1).First();

您应该使用 FirstOrDefault 进行模式防御.

You should use FirstOrDefault to be mode defensive.

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Here the dark lord teaching the force to yoda! what is the world coming to!

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