EF4未知列字段列表 [英] EF4 Unknown Column In Field List

问题描述

所以，我有点为难。我一直在使用一个通用的存储库，它完美的作品。它坐落在实体框架4.1之上。我用code的同一行获得一组数据多次，以前没有遇到任何问题。然而，在我的数据库这个表似乎是抛出一个异常，我不能为我的生活弄清楚如何解决它。

So, I am kind of stumped. I have been using a generic repository, and it works perfect. It sits on top of Entity Framework 4.1. I have used the same line of code to get a set of data numerous times and had no issues before. However, this one table in my database seems to be throwing an exception and I cannot for the life of me figure out how to fix it.

这是表的设计在MySQL数据库

This is the table design in the MySQL database

Completed
=========
CompletedId
OldStepId
NewStepId
Name

Step
====
StepId
Name
Description

这是model.cs定义

This is the model.cs definition

public class Completed
{
    [Key]
    public int CompletedId { get; set; }

    public int OldStepId { get; set; }
    public int NewStepId { get; set; }
    public string Name { get; set; }

    public virtual Step OldStep { get; set; }
    public virtual Step NewStep { get; set; }
}

public class Step
{
    [Key]
    public int StepId { get; set; }

    public string Name { get; set; }
    public string Description { get; set; }
}

上下文定义

public DbSet<Completed> Completeds { get; set; }
public DbSet<Step> Steps { get; set; }

控制器调用code问题

The controller calling code in question

var completeds = new List<Completed>();
using (var gm = new GenericRepo<Completed>())
{
  completeds = gm.Get().ToList();
}

库的GET方法（简体）

The get method of the repository (simplified)

public IEnumerable<T> Get()
{
 var context = new exampleContext();
 DbSet<T> dbSet = context.Set<T>();
 IQueryable<T> query = dbSet;
 return query.ToList();
}

这是错误导航的动作时，我从浏览器中得到

This is the error I get from the browser when navigating to the action

Unknown column 'Extent1.OldStep_StepId' in 'field list'

这是从调试器获得的内部异常

This is the inner exception obtained from the debugger

InnerException: MySql.Data.MySqlClient.MySqlException
   Message=Unknown column 'Extent1.OldStep_StepId' in 'field list'
   Source=MySql.Data
   ErrorCode=-2147467259
   Number=1054
   StackTrace:
        at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
        at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int32& insertedId)
        at MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int32& insertedId)
        at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
        at MySql.Data.MySqlClient.MySqlDataReader.NextResult()
        at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
        at MySql.Data.Entity.EFMySqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
        at System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior)
        at System.Data.EntityClient.EntityCommandDefinition.ExecuteStoreCommands(EntityCommand entityCommand, CommandBehavior behavior)

这是一个似乎已经从调试器权问题错误的应用程序崩溃前的查询

This is the query which seems to have the issue from the debugger right before the error crashes the application

{SELECT
`Extent1`.`CompletedId`, 
`Extent1`.`OldStepId`, 
`Extent1`.`NewStepId`, 
`Extent1`.`Name`, 
`Extent1`.`OldStep_StepId`, 
`Extent1`.`NewStep_StepId`, 
`Extent1`.`Step_StepId`, 
`Extent1`.`Step_StepId1`
FROM `Completed` AS `Extent1`}

使用反射，我能够确定，或者至少假设，也许StepId没有显示出来，如步骤现场的原因是因为第一步是定义为完成任何原因。这可能不是这样的。我不清楚为什么这个错误发生。

Using reflection I was able to determine, or at least assume, that perhaps the reason StepId is not showing up as a field in Step is because Step is for whatever reason defined as Completed. This may not be the case. I am unsure why this error is occurring.

有没有人遇到过这样的事情实体框架之前？这是我的code某处的一个问题？这是对表的连接方式的一个问题？我有这个设置，其中的工作完美，所以我不明白这里的差异相似的定义。此表和所有其他人之间的唯一区别是，有两个引用相同的对象（注：完成类持有两个虚拟步骤的对象）。

Has anyone encountered something like this with the Entity Framework before? Is this an issue with my code somewhere? Is this an issue of the way the tables are connected? I have similar definitions to this setup which work flawlessly so I do not understand the discrepancy here. The only difference between this table and all the others is that there are two references to the same object (Note: The Completed class holds two virtual Step objects).

另外请注意：这是不会 EF code首先

Also note: this is not EF Code First.

推荐答案

我认为这个问题是因为你还没有配置为使用已定义的FK领域的导航属性。

I think this issue is because you havent configured your navigation property to use the FK field you have defined.

您应该使用：

modelBuilder.Entity<Completed>().HasRequired(e => e.OldStep ).WithMany().HasForeignKey(e => e.OldStepId )

或尝试：

public class Completed
{
    [Key]
    public int CompletedId { get; set; }

    public int OldStepId { get; set; }
    public int NewStepId { get; set; }
    public string Name { get; set; }
        
    [ForeignKey("OldStepId")]
    public virtual Step OldStep { get; set; }

    [ForeignKey("NewStepId")]
    public virtual Step NewStep { get; set; }
}

public class Step
{
    [Key]
    public int StepId { get; set; }

    public string Name { get; set; }
    public string Description { get; set; }
}

指的http://xhalent.word$p$pss.com/2011/01/21/configuring-entity-framework-4-$c$cfirst/

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