Nested data (NHibernate components)

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You can use different classes to map specific chunks of data. For example, a Customer table might have address related column. Instead of having the address on the Customer ActiveRecord class, you could map them to an Address class.

Using a separated class

For the example stated above, we could a bad Customer ActiveRecord class declared as the example below:


using Castle.ActiveRecord;

[ActiveRecord]
public class Customer : ActiveRecordBase
{
    private int id;
    
    private string street;
    private string city;
    private string state;
    private string zipcode;
    
    [PrimaryKey]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    [Property]
    public int Street
    {
        get { return street; }
        set { street = value; }
    }

    [Property]
    public int City
    {
        get { return city; }
        set { city = value; }
    }

    [Property]
    public int State
    {
        get { return state; }
        set { state = value; }
    }

    [Property]
    public int ZipCode
    {
        get { return zipcode; }
        set { zipcode = value; }
    }
}

We can then extract the address related mapping to an Address class:


using Castle.ActiveRecord;

public class Address
{
    private string street;
    private string city;
    private string state;
    private string zipcode;
    
    [Property]
    public int Street
    {
        get { return street; }
        set { street = value; }
    }

    [Property]
    public int City
    {
        get { return city; }
        set { city = value; }
    }

    [Property]
    public int State
    {
        get { return state; }
        set { state = value; }
    }

    [Property]
    public int ZipCode
    {
        get { return zipcode; }
        set { zipcode = value; }
    }
}

Now we can simplify the Customer class code:


[ActiveRecord]
public class Customer : ActiveRecordBase
{
    private int id;
    private Address address;
    
    [PrimaryKey]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    [Nested]
    public Address Address
    {
        get { return street; }
        set { street = value; }
    }

}

You can optionaly specify a column prefix using the ColumnPrefix attribute.

Please refer to the Reference Manual's Attributes article for further information.

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Nested data (NHibernate components)

Using a separated class