--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Source/Data/Sql/SqlParameter.cs	Thu Mar 27 21:46:09 2014 +0400
@@ -0,0 +1,147 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Text;
+
+namespace BLToolkit.Data.Sql
+{
+	using Mapping;
+
+    public class SqlParameter : SqlValueBase, ISqlExpression
+	{
+		public SqlParameter(Type systemType, string name, object value, MappingSchema mappingSchema)
+		{
+			IsQueryParameter = true;
+			Name             = name;
+			SystemType       = systemType;
+			_value           = value;
+			DbType           = DbType.Object;
+
+			if (systemType != null && mappingSchema != null && systemType.IsEnum)
+			{
+			}
+		}
+
+		public SqlParameter(Type systemType, string name, object value, Converter<object,object> valueConverter)
+			: this(systemType, name, value, (MappingSchema)null)
+		{
+			ValueConverter = valueConverter;
+		}
+
+		[Obsolete]
+		public SqlParameter(string name, object value)
+			: this(value == null ? null : value.GetType(), name, value, (MappingSchema)null)
+		{
+		}
+
+		[Obsolete]
+		public SqlParameter(string name, object value, Converter<object,object> valueConverter)
+			: this(value == null ? null : value.GetType(), name, value, valueConverter)
+		{
+		}
+
+		public string Name             { get; set; }
+		public Type   SystemType       { get; set; }
+		public bool   IsQueryParameter { get; set; }
+		public DbType DbType           { get; set; }
+		public int    DbSize           { get; set; }
+
+		#region Overrides
+
+#if OVERRIDETOSTRING
+
+		public override string ToString()
+		{
+			return ((IQueryElement)this).ToString(new StringBuilder(), new Dictionary<IQueryElement,IQueryElement>()).ToString();
+		}
+
+#endif
+
+		#endregion
+
+		#region ISqlExpression Members
+
+		public int Precedence
+		{
+			get { return Sql.Precedence.Primary; }
+		}
+
+		#endregion
+
+		#region ISqlExpressionWalkable Members
+
+		ISqlExpression ISqlExpressionWalkable.Walk(bool skipColumns, Func<ISqlExpression,ISqlExpression> func)
+		{
+			return func(this);
+		}
+
+		#endregion
+
+		#region IEquatable<ISqlExpression> Members
+
+		bool IEquatable<ISqlExpression>.Equals(ISqlExpression other)
+		{
+			if (this == other)
+				return true;
+
+			var p = other as SqlParameter;
+			return (object)p != null && Name != null && p.Name != null && Name == p.Name && SystemType == p.SystemType;
+		}
+
+		#endregion
+
+		#region ISqlExpression Members
+
+		public bool CanBeNull()
+		{
+			if (SystemType == null && _value == null)
+				return true;
+
+			return SqlDataType.CanBeNull(SystemType ?? _value.GetType());
+		}
+
+		public bool Equals(ISqlExpression other, Func<ISqlExpression,ISqlExpression,bool> comparer)
+		{
+			return ((ISqlExpression)this).Equals(other) && comparer(this, other);
+		}
+
+		#endregion
+
+		#region ICloneableElement Members
+
+		public ICloneableElement Clone(Dictionary<ICloneableElement,ICloneableElement> objectTree, Predicate<ICloneableElement> doClone)
+		{
+			if (!doClone(this))
+				return this;
+
+			ICloneableElement clone;
+
+			if (!objectTree.TryGetValue(this, out clone))
+			{
+				var p = new SqlParameter(SystemType, Name, _value, ValueConverter) { IsQueryParameter = IsQueryParameter, DbType = DbType, DbSize = DbSize };
+
+				objectTree.Add(this, clone = p);
+			}
+
+			return clone;
+		}
+
+		#endregion
+
+		#region IQueryElement Members
+
+		public QueryElementType ElementType { get { return QueryElementType.SqlParameter; } }
+
+		StringBuilder IQueryElement.ToString(StringBuilder sb, Dictionary<IQueryElement,IQueryElement> dic)
+		{
+			return sb
+				.Append('@')
+				.Append(Name ?? "parameter")
+				.Append('[')
+				.Append(Value ?? "NULL")
+				.Append(']');
+		}
+
+		#endregion
+	}
+}