實體框架6和LINQ-重復記錄

Question

我有一個標准的實體框架實現，直接使用表查詢，根本不涉及任何視圖，並使用以下代碼：

var r = cxt.HistoricalQualityComponents.Where（f => f.ProducerID == activeProducer）;

一切正常，我希望有24條記錄，而我得到24條記錄。 除了查看r的內容外，我看到了第一個返回的記錄，重復了24次。 我查看生成的SQL，然后直接對數據庫運行它，並獲得24條唯一記錄。 我通過在activeProducer更改時觀察內容，甚至在LINQ查詢中應用排序來得出結論。 我不知如何解決此問題。 我的數據庫中有兩個表，但沒有其他表。

我試圖刪除.edmx實體文件，重命名了表（並生成了實體），並創建了一個完整的.aspx文件來處理該實體。 當然，我對查詢做了如下修改：

var r =從cxt.HistoricalQualityComponents中的h開始，其中h.ProducerId == activeProducer選擇h;

沒什么不同。

這可能是完全不相關的，但是在（非常懶惰）在兩個結果集上嘗試以下操作后，我注意到了此行為：

r.Sort（delegate（HistoricalQualityComponents c1，HistoricalQualityComponents c2）{return Convert.ToDateTime（c2.Pickup_Date）.CompareTo（Convert.ToDateTime（c1.Pickup_Date））;}）;

在這一點上，我只是想回到一個干凈的狀態，以便我可以實現一個模型類，該模型類將數據存儲到正確類型的對象中，並且我可以對其進行更適當的排序，但是迷失了去向下一個。

更新：生成的SQL如下：

SELECT 
    [Extent1].[RcdID] AS [RcdID], 
    [Extent1].[FieldRepID] AS [FieldRepID], 
    [Extent1].[ProducerID] AS [ProducerID], 
    [Extent1].[MonthYear_PK] AS [MonthYear_PK], 
    [Extent1].[Weight] AS [Weight], 
    [Extent1].[Fat] AS [Fat], 
    [Extent1].[Protein] AS [Protein], 
    [Extent1].[Lactose] AS [Lactose], 
    [Extent1].[SNF] AS [SNF], 
    [Extent1].[StateLeuc] AS [StateLeuc], 
    [Extent1].[Leuc] AS [Leuc], 
    [Extent1].[StateRaw] AS [StateRaw], 
    [Extent1].[Raw] AS [Raw], 
    [Extent1].[RawBracket] AS [RawBracket], 
    [Extent1].[PI] AS [PI], 
    [Extent1].[PIBracket] AS [PIBracket], 
    [Extent1].[lpc_avg] AS [lpc_avg], 
    [Extent1].[Water] AS [Water], 
    [Extent1].[AB] AS [AB], 
    [Extent1].[SED] AS [SED], 
    [Extent1].[mun] AS [mun], 
    [Extent1].[LStd] AS [LStd], 
    [Extent1].[RStd] AS [RStd], 
    [Extent1].[PStd] AS [PStd], 
    [Extent1].[SStd] AS [SStd], 
    [Extent1].[QualPremRate] AS [QualPremRate], 
    [Extent1].[QualPremAmt] AS [QualPremAmt], 
    [Extent1].[FYTDQualScore] AS [FYTDQualScore], 
    [Extent1].[FYTDQualPrem] AS [FYTDQualPrem], 
    [Extent1].[FYTDAvgQualPremRate] AS [FYTDAvgQualPremRate], 
    [Extent1].[OtherSolids] AS [OtherSolids], 
    [Extent1].[AshFactor] AS [AshFactor], 
    [Extent1].[ash_wtd_avg] AS [ash_wtd_avg], 
    [Extent1].[fat_wtd_avg] AS [fat_wtd_avg], 
    [Extent1].[leuc_wtd_avg] AS [leuc_wtd_avg], 
    [Extent1].[protein_wtd_avg] AS [protein_wtd_avg], 
    [Extent1].[os_wtd_avg] AS [os_wtd_avg], 
    [Extent1].[snf_wtd_avg] AS [snf_wtd_avg], 
    [Extent1].[iodine_wtd_avg] AS [iodine_wtd_avg]
FROM (SELECT 
    [HistoricalQualityComponents].[RcdID] AS [RcdID], 
    [HistoricalQualityComponents].[FieldRepID] AS [FieldRepID], 
    [HistoricalQualityComponents].[ProducerID] AS [ProducerID], 
    [HistoricalQualityComponents].[MonthYear_PK] AS [MonthYear_PK], 
    [HistoricalQualityComponents].[Weight] AS [Weight], 
    [HistoricalQualityComponents].[Fat] AS [Fat], 
    [HistoricalQualityComponents].[Protein] AS [Protein], 
    [HistoricalQualityComponents].[Lactose] AS [Lactose], 
    [HistoricalQualityComponents].[SNF] AS [SNF], 
    [HistoricalQualityComponents].[StateLeuc] AS [StateLeuc], 
    [HistoricalQualityComponents].[Leuc] AS [Leuc], 
    [HistoricalQualityComponents].[StateRaw] AS [StateRaw], 
    [HistoricalQualityComponents].[Raw] AS [Raw], 
    [HistoricalQualityComponents].[RawBracket] AS [RawBracket], 
    [HistoricalQualityComponents].[PI] AS [PI], 
    [HistoricalQualityComponents].[PIBracket] AS [PIBracket], 
    [HistoricalQualityComponents].[lpc_avg] AS [lpc_avg], 
    [HistoricalQualityComponents].[Water] AS [Water], 
    [HistoricalQualityComponents].[AB] AS [AB], 
    [HistoricalQualityComponents].[SED] AS [SED], 
    [HistoricalQualityComponents].[mun] AS [mun], 
    [HistoricalQualityComponents].[LStd] AS [LStd], 
    [HistoricalQualityComponents].[RStd] AS [RStd], 
    [HistoricalQualityComponents].[PStd] AS [PStd], 
    [HistoricalQualityComponents].[SStd] AS [SStd], 
    [HistoricalQualityComponents].[QualPremRate] AS [QualPremRate], 
    [HistoricalQualityComponents].[QualPremAmt] AS [QualPremAmt], 
    [HistoricalQualityComponents].[FYTDQualScore] AS [FYTDQualScore], 
    [HistoricalQualityComponents].[FYTDQualPrem] AS [FYTDQualPrem], 
    [HistoricalQualityComponents].[FYTDAvgQualPremRate] AS [FYTDAvgQualPremRate], 
    [HistoricalQualityComponents].[OtherSolids] AS [OtherSolids], 
    [HistoricalQualityComponents].[AshFactor] AS [AshFactor], 
    [HistoricalQualityComponents].[ash_wtd_avg] AS [ash_wtd_avg], 
    [HistoricalQualityComponents].[fat_wtd_avg] AS [fat_wtd_avg], 
    [HistoricalQualityComponents].[leuc_wtd_avg] AS [leuc_wtd_avg], 
    [HistoricalQualityComponents].[protein_wtd_avg] AS [protein_wtd_avg], 
    [HistoricalQualityComponents].[os_wtd_avg] AS [os_wtd_avg], 
    [HistoricalQualityComponents].[snf_wtd_avg] AS [snf_wtd_avg], 
    [HistoricalQualityComponents].[iodine_wtd_avg] AS [iodine_wtd_avg]
FROM 
    [dbo].[HistoricalQualityComponents] AS [HistoricalQualityComponents]) AS [Extent1]
WHERE 
    [Extent1].[ProducerID] = @p__linq__0

Answer 1

如果您的實體模型中的鍵與數據庫表中的鍵不匹配，則可能會發生這種情況。

例如，如果數據庫中的鍵是由(RcdID, FieldRepID)組成的復合鍵，但是在模型實體中，只有RcdID被定義為鍵，並且您運行的查詢將返回三行，其值分別為(1, 1) ， (1, 2)和(1, 3)您可能會獲得三次具有值(1, 1)的實體列表。

原因是EF僅“看到”該對的第一部分1作為密鑰。 該鍵值被返回三次。 因為EF每個鍵僅將一個對象附加到上下文，所以第一行被實現為具有鍵1的實體，但是對於第二行和第三行，則沒有新的實體被實現。 而是將第一行的已附加實體第二次和第三次添加到結果列表中。

簡而言之：檢查實體模型中定義的鍵是否與數據庫模式中的鍵匹配。