将按位枚举映射到 sql 列值 [英] Map bitwise enum to sql column value

问题描述

我有一个按位枚举，FlagsAttribute 像这样设置 -

I have a bitwise enum with FlagsAttribute set over it like this -

[FlagsAttribute]
public enum MyEnum
{
    None = 0,
    First = 1,
    Second = 2,
    Third = 4,
    Five = 8,
    Six = 16,
    Seven = 32,
    Eight = 64,
    Nine = 128
}

现在，在 C# 中，我将此值存储在一个属性中，例如 MyProperty，并在保存时将此属性写入我的 SQL 数据库的整数列中.假设如果我从代码中选择 First,Second,Five 那么在数据库中它将被保存为 '11'.

Now, in C# i am storing this value in a property say MyProperty and on save i write this property in my SQL database in integer column. Suppose if i select First,Second,Five from code then in database it will be saved as '11'.

我知道我可以从数据库中获取值，只需要将 int 值类型转换为 MyEnum，它就会给我这些值.但是，我希望在某些存储过程中对 SQL 数据进行一些操作，显然我无法将其类型转换为 Enum 值.那么，有没有办法让我知道个人价值.

I know i can fetch value from DB and just need to typecast int value to MyEnum and it will give me the values. But, i want some manipulation to be done on SQL data in some Stored procedure where obviously i can't typecast it to Enum value. So, is there a way out which can let me know about the individual values.

例如，如果存储了 11，我可以通过任何方式将其作为 "1+2+8"

Like in example if 11 is stored, any way that i can get it as "1+2+8"

推荐答案

这可能有助于您入门:

Select 11 & 1 As 'First'
  , 11 & 2 As 'Second'
  , 11 & 4 As 'Third'
  , 11 & 8 As 'Five'
  , 11 & 16 As 'Six'
  , 11 & 32 As 'Seven'
  , 11 & 64 As 'Eight'
  , 11 & 128 As 'Nine';

其中 11 是您存储的价值.

Where 11 is your stored value.

这将为设置的每个值返回非零值(即 Select 11 & 1 As 'First' 返回 1, Select 11 &; 2 As 'Second' 返回 2，Select 11 & 4 As 'Third' 返回 0 以此类推.

This will return non-zero values for each value that is set (i.e. Select 11 & 1 As 'First' returns 1, Select 11 & 2 As 'Second' returns 2, Select 11 & 4 As 'Third' returns 0 and so on.

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