--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Source/Data/Linq/DataContext.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,173 @@
+using System;
+using System.Data;
+using System.Text;
+
+namespace BLToolkit.Data.Linq
+{
+	using Data.Sql.SqlProvider;
+	using DataProvider;
+	using Mapping;
+
+	public class DataContext : IDataContext
+	{
+		public DataContext() : this(DbManager.DefaultConfiguration)
+		{
+		}
+
+		public DataContext(string configurationString)
+		{
+			ConfigurationString = configurationString;
+			DataProvider        = DbManager.GetDataProvider(configurationString);
+			ContextID           = DataProvider.Name;
+
+			MappingSchema = DataProvider.MappingSchema ?? Map.DefaultSchema;
+		}
+
+		public string           ConfigurationString { get; private set; }
+		public DataProviderBase DataProvider        { get; private set; }
+		public string           ContextID           { get; set;         }
+		public MappingSchema    MappingSchema       { get; set;         }
+		public string           LastQuery           { get; set;         }
+
+		private bool _keepConnectionAlive;
+		public  bool  KeepConnectionAlive
+		{
+			get { return _keepConnectionAlive; }
+			set
+			{
+				_keepConnectionAlive = value;
+
+				if (value == false)
+					ReleaseQuery();
+			}
+		}
+
+		private bool? _isMarsEnabled;
+		public  bool   IsMarsEnabled
+		{
+			get
+			{
+				if (_isMarsEnabled == null)
+				{
+					if (_dbManager == null)
+						return false;
+					_isMarsEnabled = _dbManager.IsMarsEnabled;
+				}
+
+				return _isMarsEnabled.Value;
+			}
+			set { _isMarsEnabled = value; }
+		}
+
+		internal int LockDbManagerCounter;
+
+		string    _connectionString;
+		DbManager _dbManager;
+
+		internal DbManager GetDBManager()
+		{
+			if (_dbManager == null)
+			{
+				if (_connectionString == null)
+					_connectionString = DbManager.GetConnectionString(ConfigurationString);
+
+				_dbManager = new DbManager(DataProvider, _connectionString) { MappingSchema = MappingSchema };
+			}
+
+			return _dbManager;
+		}
+
+		internal void ReleaseQuery()
+		{
+			LastQuery = _dbManager.LastQuery;
+
+			if (_dbManager != null && LockDbManagerCounter == 0 && KeepConnectionAlive == false)
+			{
+				_dbManager.Dispose();
+				_dbManager = null;
+			}
+		}
+
+		Func<ISqlProvider> IDataContext.CreateSqlProvider
+		{
+			get { return DataProvider.CreateSqlProvider; }
+		}
+
+		object IDataContext.SetQuery(IQueryContext queryContext)
+		{
+			var ctx = GetDBManager() as IDataContext;
+			return ctx.SetQuery(queryContext);
+		}
+
+		int IDataContext.ExecuteNonQuery(object query)
+		{
+			var ctx = GetDBManager() as IDataContext;
+			return ctx.ExecuteNonQuery(query);
+		}
+
+		object IDataContext.ExecuteScalar(object query)
+		{
+			var ctx = GetDBManager() as IDataContext;
+			return ctx.ExecuteScalar(query);
+		}
+
+		IDataReader IDataContext.ExecuteReader(object query)
+		{
+			var ctx = GetDBManager() as IDataContext;
+			return ctx.ExecuteReader(query);
+		}
+
+		void IDataContext.ReleaseQuery(object query)
+		{
+			ReleaseQuery();
+		}
+
+		string IDataContext.GetSqlText(object query)
+		{
+			if (_dbManager != null)
+				return ((IDataContext)_dbManager).GetSqlText(query);
+
+			var ctx = GetDBManager() as IDataContext;
+			var str = ctx.GetSqlText(query);
+
+			ReleaseQuery();
+
+			return str;
+		}
+
+		DataContext(int n) {}
+
+		IDataContext IDataContext.Clone(bool forNestedQuery)
+		{
+			var dc = new DataContext(0)
+			{
+				ConfigurationString = ConfigurationString,
+				KeepConnectionAlive = KeepConnectionAlive,
+				DataProvider        = DataProvider,
+				ContextID           = ContextID,
+				MappingSchema       = MappingSchema,
+			};
+
+			if (forNestedQuery && _dbManager != null && _dbManager.IsMarsEnabled)
+				dc._dbManager = _dbManager.Transaction != null ?
+					new DbManager(DataProvider, _dbManager.Transaction) { MappingSchema = MappingSchema } :
+					new DbManager(DataProvider, _dbManager.Connection)  { MappingSchema = MappingSchema };
+
+			return dc;
+		}
+
+		public event EventHandler OnClosing;
+
+		void IDisposable.Dispose()
+		{
+			if (_dbManager != null)
+			{
+				if (OnClosing != null)
+					OnClosing(this, EventArgs.Empty);
+
+				_dbManager.Dispose();
+				_dbManager = null;
+			}
+		}
+	}
+}