EF4.1中詭異的GUID為空問題

在用EF4.1過程中發現了一個非常詭異的GUID為空問題，不說廢話，直接看問題吧：

測試表UserInfo（SQL SERVER 2008 R2）：

這里是建表SQL語句，供有興趣朋友測試：

CREATE TABLE [dbo].[UserInfo](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [UserID] [uniqueidentifier] NOT NULL,
    [UserName] [nvarchar](50) NULL,
    [Email] [varchar](50) NOT NULL,
    [PicID] [uniqueidentifier] NULL,
    PRIMARY KEY([ID])
)
GO

UserInfo實體類：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.Serialization;
using System.Data.Entity;
using System.ComponentModel.DataAnnotations;

namespace ConsoleTest
{
    [Serializable]
    [DataContract]
    [Table("UserInfo")]
    public class UserInfo
    {
        [DataMember]
        [Key]
        public int ID { get; set; }

        [DataMember]
        public Guid UserID { get; set; }

        [DataMember]
        public string UserName { get; set; }

        [DataMember]
        public string Email { get; set; }

        [DataMember]
        public Guid PicID { get; set; }
    }
}

EF配置代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Entity;
using System.Configuration;

namespace ConsoleTest
{
    public class TestDBContext : DbContext
    {
        public TestDBContext()
            : base("Test")
        {
        }

        public DbSet<UserInfo> UserInfos { get; set; }
    }

}

測試方法：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

namespace ConsoleTest
{
    public class NullTest
    {
        public List<UserInfo> GetUserInfo()
        {
            using (TestDBContext context = new TestDBContext())
            {
                List<UserInfo> users = context.UserInfos
                    .Where(m=>m.UserID!=null)
                    .Where(n=>n.UserName!=null)
                    .Where(p=>p.Email!=null)
                    .Where(q=>q.PicID!=null)
                    .ToList();
                return users;
            }
        }

        public List<UserInfo> GetUserInfoNew()
        {
            using (TestDBContext context = new TestDBContext())
            {
                List<UserInfo> users = context.UserInfos
                    .Where(m => m.UserID != Guid.Empty)
                    .Where(n => n.UserName != null)
                    .Where(p => p.Email != null)
                    .Where(q => q.PicID != new Guid("00000000-0000-0000-0000-000000000000"))
                    .ToList();
                return users;
            }
        }
    }

}

調用：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace ConsoleTest
{
    class Program
    {
        static void Main(string[] args)
        {
            NullTest nullTest = new NullTest();
            nullTest.GetUserInfo();
            nullTest.GetUserInfoNew();
            Console.Read();
        }
    }

}

用SQL SERVER Profiler工具檢測到的第一個方法SQL語句：

SELECT
[Extent1].[ID] AS [ID],
[Extent1].[UserID] AS [UserID],
[Extent1].[UserName] AS [UserName],
[Extent1].[Email] AS [Email],
[Extent1].[PicID] AS [PicID]
FROM [dbo].[UserInfo] AS [Extent1]

WHERE ([Extent1].[UserName] IS NOT NULL) AND ([Extent1].[Email] IS NOT NULL)

第二個方法SQL語句：

exec sp_executesql N'SELECT

[Extent1].[ID] AS [ID],
[Extent1].[UserID] AS [UserID],
[Extent1].[UserName] AS [UserName],
[Extent1].[Email] AS [Email],
[Extent1].[PicID] AS [PicID]
FROM [dbo].[UserInfo] AS [Extent1]
WHERE ([Extent1].[UserID] <> @p__linq__0) AND ([Extent1].[UserName] IS NOT NULL) AND ([Extent1].[Email] IS NOT NULL) AND (cast(''00000000-0000-0000-0000-000000000000'' as uniqueidentifier) <> [Extent1].[PicID])',N'@p__linq__0 uniqueidentifier',@p__linq__0='00000000-0000-0000-0000-000000000000'

詭異在第一個方法生成的SQL語句中類型為GUID的兩個字段的不為空的條件沒有了，第二個方法是本人針對第一種方法不足提供的一種解決方案，不知大家有什么看法，怎么解決這一問題的，請不吝賜教！

posted @ 2011-05-04 19:44 artwl 閱讀(5152) 評論(5) 收藏舉報

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EF4.1中詭異的GUID為空問題

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