使用 EF Core 过滤时列名无效包括

Question

我在修改 DB 优先项目（使用 Fluent 迁移器）和构建 EF 上下文以生成模型时遇到此错误。我通过代码优先的简化重现了它。这意味着我不能接受建议修改注释或流畅配置的答案，因为这将在下一次迁移和脚手架时被删除并重新创建。

简化的想法是设备具有：

许多属性
代表设备随时间变化的许多历史记录
- 每个历史条目都有一个可选位置

IOW，您可以将设备移动到某个位置（或没有位置）并随着时间的推移跟踪它。

我想出的代码优先模型如下：

public class ApiContext : DbContext
{
    public ApiContext(DbContextOptions<ApiContext> options) : base(options) { }

    public DbSet<Device> Devices { get; set; }
    public DbSet<History> Histories { get; set; }
    public DbSet<Location> Locations { get; set; }
}

public class Device
{
    public int DeviceId { get; set; }
    public string DeviceName { get; set; }

    public List<History> Histories { get; } = new List<History>();
    public List<Attribute> Attributes { get; } = new List<Attribute>();
}

public class History
{
    public int HistoryId { get; set; }
    public DateTime DateFrom { get; set; }
    public string State { get; set; }

    public int DeviceId { get; set; }
    public Device Device { get; set; }

    public int? LocationId { get; set; }
    public Location Location { get; set; }
}

public class Attribute
{
    public int AttributeId { get; set; }
    public string Name { get; set; }

    public int DeviceId { get; set; }
    public Device Device { get; set; }
}

public class Location
{
    public int LocationId { get; set; }
    public string LocationName { get; set; }

    public List<History> Histories { get; } = new List<History>();
}

运行以下对 select 所有设备的查询工作正常。我使用 filtered include 仅 select 此“视图”的最新历史记录：

var devices = _apiContext.Devices.AsNoTracking()
    .Include(d => d.Histories.OrderByDescending(h => h.DateFrom).Take(1))
    .ThenInclude(h => h.Location)
    .Include(d => d.Attributes)
    .Select(d => d.ToModel()).ToList();

效果很好，但是当我尝试 select 只有一台设备使用相同的 ID 包括：

var device = _apiContext.Devices.AsNoTracking()
    .Include(d => d.Histories.OrderByDescending(h => h.DateFrom).Take(1))
    .ThenInclude(h => h.Location)
    .Include(d => d.Attributes)
    .First(d => d.DeviceId == deviceId)
    .ToModel();

我收到以下错误：

Unhandled exception. Microsoft.Data.SqlClient.SqlException (0x80131904): Invalid column name 'LocationId'.
Invalid column name 'HistoryId'.
Invalid column name 'DateFrom'.
Invalid column name 'LocationId'.
Invalid column name 'State'.
   at Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at Microsoft.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
   at Microsoft.Data.SqlClient.SqlDataReader.get_MetaData()
   at Microsoft.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString, Boolean isInternal, Boolean forDescribeParameterEncryption, Boolean shouldCacheForAlwaysEncrypted)
   at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean isAsync, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
   at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String method)
   at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at Microsoft.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
   at Microsoft.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.Enumerator.MoveNext()
   at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
   at System.Linq.Queryable.First[TSource](IQueryable`1 source, Expression`1 predicate)
   at efcore_test.App.PrintSingleDevice(Int32 deviceId) in C:\Users\Iain\projects\efcore-5-bug\efcore-test\App.cs:line 44
   at efcore_test.Program.<>c__DisplayClass1_0.<Main>b__4(App app) in C:\Users\Iain\projects\efcore-5-bug\efcore-test\Program.cs:line 28
   at efcore_test.Program.RunInScope(IServiceProvider serviceProvider, Action`1 method) in C:\Users\Iain\projects\efcore-5-bug\efcore-test\Program.cs:line 35
   at efcore_test.Program.Main(String[] args) in C:\Users\Iain\projects\efcore-5-bug\efcore-test\Program.cs:line 28
ClientConnectionId:1418edb2-0889-4f4d-9554-85344c9a35a9
Error Number:207,State:1,Class:16

我不明白为什么这适用于多行但不适用于单行。

为了完整起见，ToModel() 只是 return POCO 的扩展方法。

我什至不确定从哪里开始寻找，欢迎提出想法！

编辑

错误报告：https://github.com/dotnet/efcore/issues/26585
重现：https://github.com/thinkOfaNumber/efcore-5-test

Answer 1

更新：该bug已在EF Core 6.0中修复，所以接下来只适用于EF Core 5.0。

看起来您遇到了 EF Core 5.0 查询翻译错误，所以我建议 seek/report 将它提交给 EF Core GitHub 问题跟踪器。

据我所知，这是由于 Take 运算符（这基本上是 First 方法在第二种情况下使用的）将根查询“下推”为子查询引起的.这不知何故弄乱了生成的子查询别名并导致无效 SQL.

对比第一次查询生成的SQL可以看出

SELECT [d].[DeviceId], [d].[DeviceName], [t0].[HistoryId], [t0].[DateFrom], [t0].[DeviceId], [t0].[LocationId], [t0].[State], [t0].[LocationId0], [t0].[LocationName], [a].[AttributeId], [a].[DeviceId], [a].[Name]
FROM [Devices] AS [d]
OUTER APPLY (
    SELECT [t].[HistoryId], [t].[DateFrom], [t].[DeviceId], [t].[LocationId], [t].[State], [l].[LocationId] AS [LocationId0], [l].[LocationName]
    FROM (
        SELECT TOP(1) [h].[HistoryId], [h].[DateFrom], [h].[DeviceId], [h].[LocationId], [h].[State]
        FROM [Histories] AS [h]
        WHERE [d].[DeviceId] = [h].[DeviceId]
        ORDER BY [h].[DateFrom] DESC
    ) AS [t]
    LEFT JOIN [Locations] AS [l] ON [t].[LocationId] = [l].[LocationId]
) AS [t0]
LEFT JOIN [Attribute] AS [a] ON [d].[DeviceId] = [a].[DeviceId]
ORDER BY [d].[DeviceId], [t0].[DateFrom] DESC, [t0].[HistoryId], [t0].[LocationId0], [a].[AttributeId]

第二个（或者只是在第一个 Select 之前插入 .Where(d => d.DeviceId == deviceId).Take(1)）：

SELECT [t].[DeviceId], [t].[DeviceName], [t1].[HistoryId], [t1].[DateFrom], [t1].[DeviceId], [t1].[LocationId], [t1].[State], [t1].[LocationId0], [t1].[LocationName], [a].[AttributeId], [a].[DeviceId], [a].[Name]
FROM (
    SELECT TOP(1) [d].[DeviceId], [d].[DeviceName]
    FROM [Devices] AS [d]
    WHERE [d].[DeviceId] = @__deviceId_0
) AS [t]
OUTER APPLY (
    SELECT [t].[HistoryId], [t].[DateFrom], [t].[DeviceId], [t].[LocationId], [t].[State], [l].[LocationId] AS [LocationId0], [l].[LocationName]
    FROM (
        SELECT TOP(1) [h].[HistoryId], [h].[DateFrom], [h].[DeviceId], [h].[LocationId], [h].[State]
        FROM [Histories] AS [h]
        WHERE [t].[DeviceId] = [h].[DeviceId]
        ORDER BY [h].[DateFrom] DESC
    ) AS [t0]
    LEFT JOIN [Locations] AS [l] ON [t].[LocationId] = [l].[LocationId]
) AS [t1]
LEFT JOIN [Attribute] AS [a] ON [t].[DeviceId] = [a].[DeviceId]
ORDER BY [t].[DeviceId], [t1].[DateFrom] DESC, [t1].[HistoryId], [t1].[LocationId0], [a].[AttributeId]

注意 OUTER APPLY 中第一个 SELECT [t].[HistoryId]... 中 [t] 的用法，它在第一个查询中是 [=21] 中内部 Histories 子查询的别名=] 子句，而在第二个中，它是外部 Devices 子查询的别名，这当然没有错误消息中提到的列。显然在第二种情况下应该使用 [t0]。

既然是bug，那就等修复吧。在那之前，我建议的解决方法是在 EF Core 查询上下文之外显式执行行限制运算符 (First)，例如

var device = _apiContext.Devices.AsNoTracking()
    .Include(d => d.Histories.OrderByDescending(h => h.DateFrom).Take(1))
    .ThenInclude(h => h.Location)
    .Include(d => d.Attributes)
    .Where(d => d.DeviceId == deviceId) // instead of .First(d => d.DeviceId == deviceId)
    .AsEnumerable() // switch to client evaluation (LINQ to Objects context)
    .First() // and execute `First` here
    .ToModel();

使用 EF Core 过滤时列名无效包括

Invalid column name when using EF Core filtered includes

sql-server

asp.net-core-3.1

ef-core-5.0