Thank you kindly, TLaukkan (Tommil) for a patch that:

* Created value object for EstateRegionLink for storing the estate region relationship.
* Refactored slightly NHibernateManager and NHibernateXXXXData implementations for accesing nhibernate generated ID on insert.
** Changed NHibernateManager.Save method name to Insert as it does Insert.
** Changed NHibernateManager.Save return value object as ID can be both UUID and uint currently.
** Changed NHibernateManager.Load method Id parameter to object as it can be both UUID and uint.
* Created NHibernateEstateData implementation. This is the actual estate storage.
* Created NHibernate mapping files for both EstateSettings and EstateRegionLink
* Created MigrationSyntaxDifferences.txt files to write notes about differences in migration scripts between different databases.
* Created estate storage migration scripts for all four databases.
* Created estate unit test classes for all four databases.
* Updated one missing field to BasicEstateTest.cs
* Tested NHibernate unit tests with NUnit GUI. Asset databases fail but that is not related to this patch.
* Tested build with both Visual Studio and nant.
* Executed build tests with nant succesfully.

OpenSim/Data/NHibernate/EstateRegionLink.cs

@@ -0,0 +1,49 @@
+?using System;
+using System.Collections.Generic;
+using System.Text;
+using OpenMetaverse;
+
+namespace OpenSim.Data.NHibernate
+{
+    public class EstateRegionLink
+    {
+        private UUID estateRegionLinkID;
+        public UUID EstateRegionLinkID
+        {
+            get
+            {
+                return estateRegionLinkID;
+            }
+            set
+            {
+                estateRegionLinkID = value;
+            }
+        }
+
+        private uint estateID;
+        public uint EstateID
+        {
+            get
+            {
+                return estateID;
+            }
+            set
+            {
+                estateID = value;
+            }
+        }
+
+        private UUID regionID;
+        public UUID RegionID
+        {
+            get
+            {
+                return regionID;
+            }
+            set
+            {
+                regionID = value;
+            }
+        }
+    }
+}