实体框架代码首先通过外键进行映射

Question

I have the following tables:

Document (Id int PK, LatestVersionId int FK)
DocumentVersion (Id int PK, DocumentId int FK)

document can have one or many versions, meanwhile one version belongs to one document. And I have the following classes:

public class Document {
    public int Id {get;set;}
    public int LatestVersionId {get;set;}
    public DocumentVersion LatestVersion {get;set;}
}
public class DocumentVersion {
    public int Id {get;set;}
    public int DocumentId {get;set;}
    public Document Document {get;set;}
}

The current mappings:

HasOptional(t => t.LatestVersion).WithRequired(t => t.Document).Map(t => t.MapKey("DocumentId")) // DocumentMap
HasRequired(t => t.Document).WithOptional(t => t.LatestVersion).Map(t => t.MapKey("LatestVersionId")); // DocumentVersionMap

I'm getting the following exception: System.InvalidOperationException: The navigation property 'Document' declared on type 'DocumentVersion' has been configured with conflicting mapping information.

How should I map such relationships?

Answer 1

Can you update your class definitions as follows:

public class Document {
    [Key]
    public int Id {get;set;}

    public List<DocumentVersion> DocumentVersions {get;set;}
}

public class DocumentVersion {
    [Key]
    public int Id {get;set;}

    [ForeignKey("Document")] 
    public int DocumentId {get;set;}

    public Document Document {get;set;}
}

Fluent API:

modelBuilder.Entity<Document>()
            .HasMany(d => d.DocumentVersions)
            .WithRequired(version => version.Document)
            .HasForeignKey(version => version.DocumentId);