我在修改 DB 第一個專案（使用 fluent migrator）并搭建 EF 背景關系以生成模型時遇到了這個錯誤。我通過代碼優先的簡化復制了它。這意味著我不能接受建議修改注釋或 fluent configuration 的答案，因為這將在下一次遷移和腳手架中被洗掉和重新創建。
簡化的想法是設備具有：
- 許多屬性
- 代表設備隨時間變化的許多歷史記錄
- 每個歷史條目都有一個可選的位置
IOW 您可以將設備四處移動到某個位置（或沒有位置），并隨著時間的推移進行跟蹤。
我想出的用于模擬這個的代碼優先模型如下：
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>();
}
Running the following query to select all devices works fine. I'm using a filtered include to only select the most recent history for this "view":
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();
that works fine, however when I try and select only one device by ID using the same includes:
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();
I get the following error:
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
I can't figure out why this is working for a number of rows but not working for a single row.
For completeness, ToModel() is just an extension method to return a POCO.
I'm not even sure where to start looking, ideas welcome!
Edit
- bug report: https://github.com/dotnet/efcore/issues/26585
- repro: https://github.com/thinkOfaNumber/efcore-5-test
uj5u.com熱心網友回復：
看起來您遇到了 EF Core 查詢翻譯錯誤，因此我建議向 EF Core GitHub 問題跟蹤器尋求/報告它。
據我所知，這是由于Take運算子將根查詢“下推”為子查詢所致（這基本上First是第二種情況下使用的方法）。這以某種方式弄亂了生成的子查詢別名并導致無效的 SQL。
通過比較第一次查詢生成的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]
對于第二個（或只是在第一個.Where(d => d.DeviceId == deviceId).Take(1)之前插入Select）：
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]
注意的使用[t]在第一SELECT [t].[HistoryId]...內部的OUTER APPLY，這在拳頭查詢別名內Histories的子查詢FROM子句，而在第二它是別名外Devices子查詢，病程的具有在錯誤訊息中提到沒有列。顯然在第二種情況下[t0]應該已經使用了。
由于它是一個錯誤，您必須等待它被修復。在那之前，我可以建議的解決方法是First在 EF Core 查詢背景關系之外顯式執行行限制運算子 ( )，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();
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標籤：sql-server asp.net-core-3.1 entity-framework-core-5