实体框架6和LINQ-重复记录

Question

I have a standard entity framework implementation querying directly against a table, no views involved at all, with the following code:

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

Everything works properly, I would expect 24 records and I get 24 records. Except that when I look at the contents of r, I see the first returned record, repeated 24 times. I look at the generated SQL and run it directly against the database and I get 24 unique records. I conclude this by observing the contents while activeProducer changes, or even applying a sort as part of the LINQ query. I'm at a loss at how to fix this. This occurs with two tables in my database, but no others.

I've tried to delete my .edmx entity file, I renamed the table (and generated entity), and created an entirely .aspx file to process the entity. Of course, I reworked the query as such:

var r = from h in cxt.HistoricalQualityComponents where h.ProducerId == activeProducer select h;

Didn't make a difference.

It may be entirely irrelevant, but I noticed this behavior after (very lazily) trying the following on both result sets:

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

At this point, I'd simply like to get back to a clean state so that I can implement a model class that will store the data into a properly typed object and I can sort it more appropriately but am at a loss on where to go next.

UPDATE: The generated SQL follows:

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

It could happen if the keys in your entity model don't match the keys in the database table.

For example, if the key in the database is composite consisting of (RcdID, FieldRepID) but in your model entity only RcdID is defined as key and you run a query that would return three rows with values (1, 1) , (1, 2) and (1, 3) you would probably get a list of the entity with the values (1, 1) three times.

The reason is that EF only "sees" the first part 1 of the pair as key. This key value is returned three times. Because EF attaches only one object per key to the context the first row is materialized to an entity with key 1 , but for the second and third row no new entity is materialized. Instead the already attached entity of the first row is added a second and third time to the result list.

Long story short: Check if the keys defined in the entity model match the keys in the database schema.