BelongsTo

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A many-to-one relation can be mapped using the BelongsToAttribute

Consider the following table script:


CREATE TABLE Blogs 
(
    [id] [int] IDENTITY (1, 1) NOT NULL,
    [name] [varchar] (50) NULL
) ON [PRIMARY]

CREATE TABLE Posts 
(
    [id] [int] IDENTITY (1, 1) NOT NULL,
    [title] [varchar] (50) NULL,
    [contents] [text] NULL,
    [blogid] [int] NULL
) ON [PRIMARY]

The blogid on Posts is clear a foreign key to the Blogs table. You can map the reference on the Post to a Blog, and to do it you can use BelongsToAttribute:


using Castle.ActiveRecord;

[ActiveRecord("posts")]
public class Post : ActiveRecordBase
{
    private int id;
    private string title;
    private string contents;
    private Blog blog;
    
    [PrimaryKey]
    public int Id
    {
        get { return id; }
        set { id = value; }
    }

    [Property]
    public string Title
    {
        get { return title; }
        set { title = value; }
    }

    [Property(ColumnType="StringClob")]
    public string Contents
    {
        get { return contents; }
        set { contents = value; }
    }
    
    [BelongsTo("blogid")]
    public Blog OwnerBlog
    {
        get { return blog; }
        set { blog = value; }
    }
}

Assigning a blog instance to this property - and obviously saving the post instance - will create the association.

More information on the attribute can be found at Attributes article.

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BelongsTo