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POError Related to FK in One-to-Many Relationship
 

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  1. POError Related to FK in One-to-Many Relationship
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    <p>I am using EF 5 Beta 2 Code-First. I have created an edmx file which has 2 entities among others named <em>Brand</em> and <em>Vehicle</em>.</p> <p>One <em>Brand</em> can have zero or more (many) <em>Vehicles</em> and every <em>Vehicle</em> should have a <em>Brand</em> (required). <em>Vehicle</em> has a foreign key named <em>BrandID</em> which is <em>non-nullable</em>.</p> <pre><code>(relationship) Brand +-------------------&gt; Vehicle (1) (*) </code></pre> <p>Also I did use <em>EF 5 DbContext Generator</em> to create POCO classes.</p> <h2>The Problem</h2> <p>When I try to either Read or Write records, I get the following error:</p> <p><strong>error 3023: Problem in mapping fragments starting at line 155:Column Vehicle.BrandID in table Vehicle must be mapped: It has no default value and is not nullable.</strong></p> <p>Notice: I am using <strong>TPC</strong> inheritance mapping where Vehicle is an <em>abstract base class</em> from which 2 classes (<em>Car</em> &amp; <em>Motorbike</em>) are being derived.</p> <p>Here is class definition plus related fluent API code:</p> <pre><code>//------------ Class definiions --------------- public abstract partial class Vehicle { public int VehicleID { get; set; } public short BrandID { get; set; } public virtual Brand Brand { get; set; } public partial class Car : Vehicle { public string BodyType { get; set; } } public partial class Motorbike : Vehicle { } public partial class Brand { public Brand() { this.Vehicles = new HashSet&lt;Vehicle&gt;(); } public short BrandID { get; set; } public string Name { get; set; } public virtual ICollection&lt;Vehicle&gt; Vehicles { get; set; } } //--------------- Fluent API code --------------- modelBuilder.Entity&lt;Vehicle&gt;() .Property(p =&gt; p.VehicleID) .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity); modelBuilder.Entity&lt;Car&gt;() .Map(m =&gt; { m.ToTable("Car"); m.MapInheritedProperties(); }); modelBuilder.Entity&lt;Motorbike&gt;() .Map(m =&gt; { m.ToTable("Motorbike"); m.MapInheritedProperties(); }); modelBuilder.Entity&lt;Brand&gt;() .HasMany(b=&gt;b.Vehicles) .WithRequired(v=&gt;v.Brand) .HasForeignKey(p =&gt; p.BrandID); modelBuilder.Entity&lt;Brand&gt;() .Property(p =&gt; p.BrandID) .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity); </code></pre> <p>This is so strange since everything seems OK and has been checked several times.</p> <p>Any thoughts would be greatly appreciated.</p>
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    1. PO
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    1. This table or related slice is empty.
    1. PTQuestion
    1. USom-nom-nom
    1. USKamran
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. POError Related to FK in One-to-Many Relationship
      1. This table or related slice is empty.
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    2. VO
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      1. POError Related to FK in One-to-Many Relationship
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      1. VTUpMod
    1. CODo you really have a `Vehicle` table as the exception says? I'm wondering because if you use TPC you should not have a table for the abstract base class, only for the two concrete classes `Car` and `Motorbike`. Also: Do you have a connection string with all the edm metadata stuff in it? I would expect that because apparently you use Model-First. But I'm wondering why you have Fluent API mapping code, which is Code-First and not Model-First.
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      1. POError Related to FK in One-to-Many Relationship
      1. USSlauma
    2. CO@Slauma: 1. Another strange thing - as you mentioned - is that I have a `Vehicle` class, while this does not happen for another abstract base class named `Ad` and its derived classes. 2. My connection string is as follows: <add name="IranCarContext" providerName="System.Data.SqlClient" connectionString="Data Source=localhost;Initial Catalog=IranCar;Integrated Security=SSPI;" /> 3. About Model-First: first I used EDM Designer to model my entities visually. Then I used **EF DbContext Generator** to create POCO classes and `DbContext`. Finally I used EF + Fluent API to create the databse.
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      1. POError Related to FK in One-to-Many Relationship
      1. USKamran
    3. COPerhaps it would help if you show the full mapping in Fluent API for the classes above, especially also the TPC mapping. Having a navigation property (`Brand`) on the *base class* (`Vehicle`) is a possible problem with TPC: http://weblogs.asp.net/manavi/archive/2011/01/03/inheritance-mapping-strategies-with-entity-framework-code-first-ctp5-part-3-table-per-concrete-type-tpc-and-choosing-strategy-guidelines.aspx (see section "Polymorphic Associations with TPC is Problematic" in this article).
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      1. POError Related to FK in One-to-Many Relationship
      1. USSlauma
 

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