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Entity Framework StoreGeneratedPattern Bug Persists

October 24, 2010

I’m using System.Data.SQLite v1.0.66.0 with Entity Framework 4.0 and Visual Studio 2010.  I designed some tables in SQLite and generated an Entity Data Model from those tables.  One of them (we’ll call it Person for the sake of argument) has an autogenerated integer primary key.  I manually set the StoreGeneratedPattern property to Identity in the designer, but when I started creating new rows in the database I encountered a problem.

I create new Person entities with a dummy PersonID of -1.  The first row inserts fine, but instead of generating a new ID it uses the dummy value.  That means when I insert the second row, it fails:

Abort due to constraint violation
PRIMARY KEY must be unique

I did a little Googling and realized I’m not the only person experiencing this:

It seems there is a bug in which the StoragePattern property is not updated in the SSDL when you change it in the designer, even though the CSDL is.

The impact of this is that you have to open the .edmx file in the XML editor and manually add the StorageGeneratedPattern property to the definition for your entity in the StorageModels section:

<EntityType Name="Person">
        <PropertyRef Name="PersonID" />
    <Property Name="PersonID" Type="integer" Nullable="false" StoreGeneratedPattern="Identity" />
    <Property Name="Name" Type="nvarchar" Nullable="false" MaxLength="50" />
    <Property Name="Age" Type="integer" Nullable="false" />

Even worse, you’ll have to do this for every identity column every time you update the model from the database because the property gets clobbered.  The workaround does work, technically, but it’s a major nuisance during development when things change often.

Identity columns are not uncommon, which means that this issue should have been uncovered early during testing.  Why didn’t Microsoft fix it right away?  According to some claims, it’s been around since EF 1.0.  In a couple of weeks I’m starting a new job where they use NHibernate.  It will be interesting to compare it to EF 4.0 and see if I run into the same kind of bugs.  Perhaps it will also help to wean me off graphical designers altogether.


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  1. This bug is becoming very annoying as my models grow. The only way I’ve found to ease the pain to to use compare against the latest version and copy the missing StoredGenerationPattern properties.

    Microsoft please fix this!

  2. Can’t believe this is a bug…. I usually use nhibernate…. serves me right for giving EF a try. 😛 Do u know if its fixed at all?

    • I don’t think it has been fixed yet, but the GUI designer is a much smaller part of my development workflow in EF since I wrote this article. I’ve been experimenting with “Code-First” and find it a lot more natural to use. In fact, it’s a bit more like NHibernate. 🙂

  3. Sarah McDevitt permalink

    We have released a hotfix for the StoreGeneratedPattern issue. Try it out! Also great to hear you are enjoying Code First!

    Code Gallery:

    Thank you,
    Sarah McDevitt
    Program Manager, Microsoft

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