如何更改Entity Framework为Datetime生成SQL精度的方式

Question

我有一个表使用id和DateTime列是pk,但当我尝试通过Entity Framework更新数据时,如下所示:

using (Entities context = new Entities())
{
    var item = (from item in context.BatchData
                where item.Id == 2
                select item ).FirstOrDefault();

    item.Title = "EF6TEST";

    context.SaveChanges();
}

我收到一个错误

存储更新,插入或删除语句会影响意外的行数(0).

记录SQL后,我知道原因.

SQL看起来像这样

'update [dbo].[BatchData]
set [BatchData_Title] = @0
where (([BatchData_Id] = @1) and ([BatchData_CreatedDateTime] = @2))

select [BatchData_Rowversion]
from [dbo].[BatchData]BatchUploadData
where @@ROWCOUNT > 0 and [BatchData_Id] = @1 and [BatchData_CreatedDateTime]     = @2',
N'@0 varchar(30),@1 tinyint,@2 datetime2(7)',
@0='EF6TEST',@1=1,@2='2017-09-16 11:29:35.3720000'

所以,原因是BatchData_CreatedDateTimeSQL中的参数是@2='2017-09-16 11:29:35.3720000',精度是7,它应该是@2='2017-09-16 11:29:35.372'.

这是我的问题,如何解决？

Answer 1

您可以使用IDbInterceptor来改变所需要的数据,这里是从变化的参数类型的拦截器的一个例子DateTime2来DateTime,你可以扩展它来使用它在你的DB /的DbCommand参数的具体领域.

public class DateInterceptor : IDbInterceptor, IDbCommandInterceptor
{
    public void ReaderExecuting(DbCommand command, 
        DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        var dateParameters = command.Parameters.OfType<DbParameter>()
            .Where(p => p.DbType == DbType.DateTime2);
        foreach (var parameter in dateParameters)
        {
            parameter.DbType = DbType.DateTime;
        }
    }

要使用它,请添加DbInterception.Add(new DateInterceptor());到OnModelCreatingdbContext类的末尾

生成的SQL将从中更改

@ 2 datetime2(7)',@ 0 = 0,@ 1 = 1,@ 2 ='2017-09-24 14:41:33.7950485'

至

@ 2 datetime',@ 0 = 0,@ 1 = 1,@ 2 ='2017-09-24 14:40:32.327'