[Solved] I cannot make association in my database (Fluent)

[Marko Gluhak]

Hi,

 

I'm starting to use Fluent Mapping and I have stuck on creating association. I have self referenced class. Fields are: private int _idCategory;

private int _idCategory;
public int IdCategory
{
    get { return _idCategory; }
    set { _idCategory = value; }
}

private int _idCategoryParent;
public int IdCategoryParent
{
    get { return _idCategoryParent; }
    set { _idCategoryParent = value; }
}

private bool _isLeaf;
public bool IsLeaf
{
    get { return _isLeaf; }
    set { _isLeaf = value; }
}

private string _categoryName;
public string CategoryName
{
    get { return _categoryName; }
    set { _categoryName = value; }
}

private string _categoryDescription;
public string CategoryDescription
{
    get { return _categoryDescription; }
    set { _categoryDescription = value; }
}

public cCategory()
{
    CategoryName = "SomeValue";
    CategoryDescription = "SomeValue";
    IsLeaf = false;
}


/* ASSOCIATIONS */
private IList<cCategory> _childCategories = new List<cCategory>();
public virtual IList<cCategory> ChildCategories
{
    get
    {
        return this._childCategories;
    }
}

private cCategory _parentCategory;
public virtual cCategory ParentCategory
{
    get
    {
        return this._parentCategory;
    }
    set
    {
        this._parentCategory = value;
    }
}

I have metadatasource:

protected override IList<MappingConfiguration> PrepareMapping()
{
    var mappingConfigurations = new List<MappingConfiguration>();

    MappingConfiguration<cCategory> categoryConfiguration = this.Get_Category_Configuration();
    mappingConfigurations.Add(categoryConfiguration);

    return mappingConfigurations;
}

protected override MetadataContainer CreateModel()
{
    Telerik.OpenAccess.Metadata.MetadataContainer model = base.CreateModel();
    model.DefaultMapping.NullForeignKey = true;
    return model;
}


#region Category table
/********************************************************************************                                            CATEGORY
********************************************************************************/
public MappingConfiguration<cCategory> Get_Category_Configuration()
{
    MappingConfiguration<cCategory> configuration = this.Get_Category_ClassConfiguration();
    this.Prepare_Category_PropertyConfigurations(configuration);
    this.Prepare_Category_AssociationConfigurations(configuration);
    return configuration;
}

public MappingConfiguration<cCategory> Get_Category_ClassConfiguration()
{
    var configuration = new MappingConfiguration<cCategory>();

    var namingRules = new Telerik.OpenAccess.Metadata.NamingRules();
    namingRules.CaseMode = Telerik.OpenAccess.Metadata.CaseChangeModes.CamelCase;
    namingRules.AddPrefix = "_";
    configuration.FieldNamingRules = namingRules;

    configuration.MapType(x => new { }).WithDataAccessKind(DataAccessKind.ReadOnly).WithConcurencyControl(OptimisticConcurrencyControlStrategy.Changed).ToTable(tableName: "Category");

    return configuration;
}


public void Prepare_Category_PropertyConfigurations(MappingConfiguration<cCategory> configuration)
{
    configuration.HasProperty(x => x.IdCategory).IsIdentity(KeyGenerator.Autoinc).WithDataAccessKind(DataAccessKind.ReadWrite).ToColumn(columnName: "IdCategory").IsNullable().HasColumnType(typeName: "int").HasPrecision(precision: 0).HasScale(scale: 0);
    configuration.HasProperty(x => x.IdCategoryParent).WithDataAccessKind(DataAccessKind.ReadWrite).ToColumn(columnName: "IdCategoryParent").IsNullable().HasColumnType(typeName: "int").HasPrecision(precision: 0).HasScale(scale: 0);
    configuration.HasProperty(x => x.IsLeaf).WithDataAccessKind(DataAccessKind.ReadWrite).ToColumn(columnName: "IsLeaf").IsNotNullable().HasColumnType(typeName: "bit").HasPrecision(precision: 0).HasScale(scale: 0);
    configuration.HasProperty(x => x.CategoryName).WithDataAccessKind(DataAccessKind.ReadWrite).ToColumn(columnName: "CategoryName").IsNotNullable().HasColumnType(typeName: "nvarchar").HasLength(length: 50);
    configuration.HasProperty(x => x.CategoryDescription).WithDataAccessKind(DataAccessKind.ReadWrite).ToColumn(columnName: "CategoryDescription").IsNotNullable().HasColumnType(typeName: "nvarchar").HasLength(length: 255);

}

public void Prepare_Category_AssociationConfigurations(MappingConfiguration<cCategory> configuration)
{
    configuration.HasAssociation(x => x.ChildCategories).WithOpposite(x => x.ParentCategory).HasConstraint((x, y) => x.IdCategoryParent == y.IdCategory).IsManaged().WithDataAccessKind(DataAccessKind.ReadWrite);
}


#endregion

Table is created but no association and foreign key is created in DB.

With regards,
Marko

[Pavel Uzunov]

Hi Marko Gluhak,

Your code is absolutely fine and it works correctly, but Telerik Data Access does not support constraints on self-referencing associations because they need special handling of the insert and delete order. For normal one-to-many associations Data Access calculated this order based on the table definitions and first inserts the record holding the primary key. But for self-references, the table is only one and this mechanism does not work, also there could be cyclic references that could cause problems.
I am afraid that you will not be able to create those constraints automatically and the only option at the moment is to do that manually in the database.

I hope the provided information is helpful.

Regards,
Pavel Uzunov
Telerik