CREATE TABLE [dbo].[Categories](
   [Id] [bigint] IDENTITY(1,1) NOT NULL,
   [Name] [varchar](50) COLLATE Polish_CI_AS NOT NULL,
   [Description] [varchar](255) COLLATE Polish_CI_AS NULL,
CONSTRAINT [PK_Categories] PRIMARY KEY CLUSTERED
(
   [Id] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

CREATE TABLE [dbo].[CategoriesTree](
   [CategoryId] [bigint] NOT NULL,
   [ParentCategoryId] [bigint] NOT NULL,
CONSTRAINT [PK_CategoriesTree] PRIMARY KEY CLUSTERED
(
   [CategoryId] ASC,
   [ParentCategoryId] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]

ALTER TABLE [dbo].[CategoriesTree]  WITH CHECK ADD  CONSTRAINT [FK_CategoriesTree_Categories] FOREIGN KEY([CategoryId])
REFERENCES [dbo].[Categories] ([Id])
GO
ALTER TABLE [dbo].[CategoriesTree]  WITH CHECK ADD  CONSTRAINT [FK_CategoriesTree_Categories1] FOREIGN KEY([ParentCategoryId])
REFERENCES [dbo].[Categories] ([Id])

CREATE TABLE [dbo].[Products](
   [Id] [bigint] IDENTITY(1,1) NOT NULL,
   [ProducerId] [bigint] NOT NULL,
   [CategoryId] [bigint] NOT NULL,
   [Name] [varchar](50) COLLATE Polish_CI_AS NOT NULL,
   [Description] [text] COLLATE Polish_CI_AS NULL,
   [Price] [decimal](9, 2) NOT NULL,
   [Amount] [int] NOT NULL,
   [FromDate] [smalldatetime] NOT NULL,
CONSTRAINT [PK_Products] PRIMARY KEY CLUSTERED
(
   [Id] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

ALTER TABLE [dbo].[Products]  WITH CHECK ADD  CONSTRAINT [FK_Products_Categories] FOREIGN KEY([CategoryId])
REFERENCES [dbo].[Categories] ([Id])
GO
ALTER TABLE [dbo].[Products]  WITH CHECK ADD  CONSTRAINT [FK_Products_Producers] FOREIGN KEY([ProducerId])
REFERENCES [dbo].[Producers] ([Id])

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0" assembly="NCommercePersistence" namespace="NCommerce.Persistence">
   <class name="Category" table="CategoriesV">
      <id name="Id" column="Id" type="Int64">
         <generator class="identity"/>
      </id>
      <property name="Name" column="Name" type="String" length="50"/>
      <property name="Description" column="Description" type="String"/>
      <set name="Products" table="Products">
         <key column="CategoryId"/>
         <one-to-many class="Product"/>
      </set>
      <set name="ChildrenCategories" table="CategoriesTree">
         <key column="ParentCategoryId"/>
         <many-to-many column="CategoryId"  class="Category"/>
      </set>
      <many-to-one name="ParentCategory" column="ParentCategoryId"  class="Category"/>
   </class>
</hibernate-mapping>