Entity framework query returns the same row multiple times

Question

This is my first time using the Entity Framework and I'm getting some confusing results. I know a particular table contains 3 distinct rows when I run this SQL query:

SELECT * FROM mytable WHERE service_month = 201012

When I run this query against the framework however, I get 3 rows, but they are all copies of the first row (VB syntax).

Dim temp = _context.mytable.Where(Function(x) x.service_month = 201012)

Did I set up something incorrectly? This is how I'd do it with LINQ to SQL so I feel like I'm missing something.

what are you then doing with temp to check the values?

Tim B James
– Tim B James

2011-08-31 12:56:32 +00:00
Commented Aug 31, 2011 at 12:56 — Tim B James
– Tim B James, Commented Aug 31, 2011 at 12:56

Craig Stuntz · Accepted Answer · 2011-08-31 12:55:48Z

41

Fix your primary key definition in your EDMX. (If your table has no PK, add one.) When all rows return the same "key", the EF returns the same object instance.

answered Aug 31, 2011 at 12:55

Craig Stuntz

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4 Comments

gfrizzle Over a year ago

Bingo. I'm using reporting tables set up by someone else and they didn't have a primary key. Thanks.

Chris B Over a year ago

Even if the developers call this a feature, I'm calling it a bug. Thanks a lot for the solution.

Ranjith Varatharajan Over a year ago

Thanks @Craig. Just now found out that the table i'm working on, has no primary key.

Guy Lowe Over a year ago

Wow. Was seleting from a view that had no key. I had to set the Date field (only unique field in view) to the EntityKey in the edmx and all is fine.

Kirsten · Accepted Answer · 2022-02-09 11:15:56Z

0

I experienced this in Code First 5.0.13 when I had used a [Key] attribute in the business object that came from the wrong library. It should be

System.ComponentModel.DataAnnotations.KeyAttribute

answered Feb 9, 2022 at 11:15

Kirsten

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