mono/mcs/class/System.Data/System.Data.SqlClient/SqlCommandBuilder.cs

//
// System.Data.SqlClient.SqlCommandBuilder.cs
//
// Author:
//   Tim Coleman ([email protected])
//
// Copyright (C) Tim Coleman, 2002
//

//
// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.Common;
#if NET_2_0
using System.Data.SqlTypes;
#endif
using System.Text;

namespace System.Data.SqlClient
{
#if NET_2_0
	public sealed class SqlCommandBuilder : DbCommandBuilder
#else
	public sealed class SqlCommandBuilder : Component
#endif // NET_2_0
	{
		#region Fields

		bool disposed;

		DataTable dbSchemaTable;
#if ONLY_1_1
		string quotePrefix;
		string quoteSuffix;
#endif
		string tableName;
#if NET_2_0
		readonly string _catalogSeparator = ".";
		readonly string _schemaSeparator = ".";
		readonly CatalogLocation _catalogLocation = CatalogLocation.Start;
#endif
#if ONLY_1_1
		SqlDataAdapter adapter;
		SqlCommand insertCommand;
		SqlCommand deleteCommand;
		SqlCommand updateCommand;
#endif
	
		// Used to construct WHERE clauses
		static readonly string clause1 = "({0} = 1 AND {1} IS NULL)";
		static readonly string clause2 = "({0} = {1})";

		private SqlRowUpdatingEventHandler rowUpdatingHandler;

		#endregion // Fields

		#region Constructors

		public SqlCommandBuilder ()
		{
#if NET_2_0
			QuoteSuffix = "]";
			QuotePrefix = "[";
#endif
		}

		public SqlCommandBuilder (SqlDataAdapter adapter)
			: this ()
		{
			DataAdapter = adapter;
		}

		#endregion // Constructors

		#region Properties

#if !NET_2_0
		[DataSysDescription ("The DataAdapter for which to automatically generate SqlCommands")]
#endif
		[DefaultValue (null)]
		public new SqlDataAdapter DataAdapter {
			get { 
#if ONLY_1_1
				return adapter;
#else
				return (SqlDataAdapter)base.DataAdapter;
#endif
			} set {
#if ONLY_1_1
               if (adapter != null)
                       adapter.RowUpdating -= new SqlRowUpdatingEventHandler (RowUpdatingHandler);

               adapter = value; 
               if (adapter != null)
                       adapter.RowUpdating += new SqlRowUpdatingEventHandler (RowUpdatingHandler);
#else
				base.DataAdapter = value;
#endif
			}
		}

		private string QuotedTableName {
			get { return GetQuotedString (tableName); }
		}

		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if !NET_2_0
		[DataSysDescription ("The character used in a text command as the opening quote for quoting identifiers that contain special characters.")]
#else
		[EditorBrowsable (EditorBrowsableState.Never)]
#endif // NET_2_0
		public
#if NET_2_0
		override
#endif // NET_2_0
		string QuotePrefix {
			get {
#if ONLY_1_1
				if (quotePrefix == null)
					return string.Empty;
				return quotePrefix;
#else
				return base.QuotePrefix;
#endif
			}
			set {
#if ONLY_1_1
				if (dbSchemaTable != null)
					throw new InvalidOperationException (
						"The QuotePrefix and QuoteSuffix " +
						"properties cannot be changed once " +
						"an Insert, Update, or Delete " +
						"command has been generated.");
				quotePrefix = value;
#else
				if (value != "[" && value != "\"")
					throw new ArgumentException ("Only '[' " +
						"and '\"' are allowed as value " +
						"for the 'QuoteSuffix' property.");
				base.QuotePrefix = value;
#endif
			}
		}

		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if !NET_2_0
		[DataSysDescription ("The character used in a text command as the closing quote for quoting identifiers that contain special characters. ")]
#else
		[EditorBrowsable (EditorBrowsableState.Never)]
#endif // NET_2_0
		public
#if NET_2_0
		override
#endif // NET_2_0
		string QuoteSuffix {
			get {
#if ONLY_1_1
				if (quoteSuffix == null)
					return string.Empty;
				return quoteSuffix;
#else
				return base.QuoteSuffix;
#endif
			}
			set {
#if ONLY_1_1
				if (dbSchemaTable != null)
					throw new InvalidOperationException (
						"The QuotePrefix and QuoteSuffix " +
						"properties cannot be changed once " +
						"an Insert, Update, or Delete " +
						"command has been generated.");
				quoteSuffix = value;
#else
				if (value != "]" && value != "\"")
					throw new ArgumentException ("Only ']' " +
						"and '\"' are allowed as value " +
						"for the 'QuoteSuffix' property.");
				base.QuoteSuffix = value;
#endif
			}
		}

#if NET_2_0
		[EditorBrowsable (EditorBrowsableState.Never)]
		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if !NET_2_0
		[DefaultValue (".")]
#endif
		public override string CatalogSeparator {
			get { return _catalogSeparator; }
			set {
				if (value != _catalogSeparator)
					throw new ArgumentException ("Only " +
						"'.' is allowed as value " +
						"for the 'CatalogSeparator' " +
						"property.");
			}
		}

		[EditorBrowsable (EditorBrowsableState.Never)]
		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if !NET_2_0
		[DefaultValue (".")]
#endif
		public override string SchemaSeparator {
			get { return _schemaSeparator; }
			set {
				if (value != _schemaSeparator)
					throw new ArgumentException ("Only " +
						"'.' is allowed as value " +
						"for the 'SchemaSeparator' " +
						"property.");
			}
		}

		[EditorBrowsable (EditorBrowsableState.Never)]
		[Browsable (false)]
		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if !NET_2_0
		[DefaultValue (CatalogLocation.Start)]
#endif
		public override CatalogLocation CatalogLocation {
			get { return _catalogLocation; }
			set {
				if (value != CatalogLocation.Start)
					throw new ArgumentException ("Only " +
						"'Start' is allowed as value " +
						"for the 'CatalogLocation' " +
						"property.");
			}
		}

#endif // NET_2_0

#if ONLY_1_1
		private SqlCommand SourceCommand {
			get {
				if (adapter != null)
					return adapter.SelectCommand;
				return null;
			}
		}
#endif

		#endregion // Properties

		#region Methods

#if ONLY_1_1
		private void BuildCache (bool closeConnection)
		{
			SqlCommand sourceCommand = SourceCommand;
			if (sourceCommand == null)
				throw new InvalidOperationException ("The DataAdapter.SelectCommand property needs to be initialized.");
			SqlConnection connection = sourceCommand.Connection;
			if (connection == null)
				throw new InvalidOperationException ("The DataAdapter.SelectCommand.Connection property needs to be initialized.");

			if (dbSchemaTable == null) {
				if (connection.State == ConnectionState.Open)
					closeConnection = false;
				else
					connection.Open ();

				SqlDataReader reader = sourceCommand.ExecuteReader (CommandBehavior.SchemaOnly | CommandBehavior.KeyInfo);
				dbSchemaTable = reader.GetSchemaTable ();
				reader.Close ();
				if (closeConnection)
					connection.Close ();
				BuildInformation (dbSchemaTable);
			}
		}
		
		private void BuildInformation (DataTable schemaTable)
		{
			tableName = String.Empty;
			foreach (DataRow schemaRow in schemaTable.Rows) {
				if (schemaRow.IsNull ("BaseTableName") ||
				    (string) schemaRow ["BaseTableName"] == String.Empty)
					continue;

				if (tableName == String.Empty) 
					tableName = (string) schemaRow ["BaseTableName"];
				else if (tableName != (string) schemaRow["BaseTableName"])
					throw new InvalidOperationException ("Dynamic SQL generation is not supported against multiple base tables.");
			}
			if (tableName == String.Empty)
				throw new InvalidOperationException ("Dynamic SQL generation is not supported with no base table.");
			dbSchemaTable = schemaTable;
		}

		private SqlCommand CreateDeleteCommand (bool useColumnsForParameterNames)
		{
			// If no table was found, then we can't do an delete
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref deleteCommand);

			string command = String.Format ("DELETE FROM  {0}", QuotedTableName);
			StringBuilder whereClause = new StringBuilder ();
			bool keyFound = false;
			int parmIndex = 1;

			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if ((bool)schemaRow["IsExpression"] == true)
					continue;
				if (!IncludedInWhereClause (schemaRow)) 
					continue;

				if (whereClause.Length > 0) 
					whereClause.Append (" AND ");

				bool isKey = (bool) schemaRow ["IsKey"];
				SqlParameter parameter = null;

				if (isKey)
					keyFound = true;

				bool allowNull = (bool) schemaRow ["AllowDBNull"];
				if (!isKey) {
					string sourceColumnName = (string) schemaRow ["BaseColumnName"];
					if (useColumnsForParameterNames) {
						parameter = deleteCommand.Parameters.Add (
							GetNullCheckParameterName (sourceColumnName),
							SqlDbType.Int);
					} else {
						parameter = deleteCommand.Parameters.Add (
							GetParameterName (parmIndex++),
							SqlDbType.Int);
					}
					parameter.IsNullable = allowNull;
					parameter.SourceVersion = DataRowVersion.Current;
					parameter.Value = 1;

					whereClause.Append ("(");
					whereClause.Append (String.Format (clause1, parameter.ParameterName,
									GetQuotedString (sourceColumnName)));
					whereClause.Append (" OR ");
				}

				if (useColumnsForParameterNames)
					parameter = CreateParameter (schemaRow, true);
				else
					parameter = CreateParameter (parmIndex++, schemaRow);
				deleteCommand.Parameters.Add (parameter);
				ApplyParameterInfo (parameter, schemaRow, StatementType.Delete, true);
				parameter.IsNullable = allowNull;
				parameter.SourceVersion = DataRowVersion.Original;

				whereClause.Append (String.Format (clause2, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));

				if (!isKey)
					whereClause.Append (")");
			}
			if (!keyFound)
				throw new InvalidOperationException ("Dynamic SQL generation for the DeleteCommand is not supported against a SelectCommand that does not return any key column information.");

			// We're all done, so bring it on home
			string sql = String.Format ("{0} WHERE ( {1} )", command, whereClause.ToString ());
			deleteCommand.CommandText = sql;
			return deleteCommand;
		}

		private SqlCommand CreateInsertCommand (bool useColumnsForParameterNames)
		{
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref insertCommand);

			string command = String.Format ("INSERT INTO {0}", QuotedTableName);
			string sql;
			StringBuilder columns = new StringBuilder ();
			StringBuilder values = new StringBuilder ();

			int parmIndex = 1;
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (!IncludedInInsert (schemaRow))
					continue;

				if (parmIndex > 1) {
					columns.Append (" , ");
					values.Append (" , ");
				}

				SqlParameter parameter = null;
				if (useColumnsForParameterNames) {
					parameter = CreateParameter (schemaRow, false);
				} else {
					parameter = CreateParameter (parmIndex, schemaRow);
				}

				insertCommand.Parameters.Add (parameter);
				ApplyParameterInfo (parameter, schemaRow, StatementType.Insert, false);
				parameter.SourceVersion = DataRowVersion.Current;
				parameter.IsNullable = (bool) schemaRow ["AllowDBNull"];

				columns.Append (GetQuotedString (parameter.SourceColumn));
				values.Append (parameter.ParameterName);

				parmIndex++;
			}

			sql = String.Format ("{0}( {1} ) VALUES ( {2} )", command, columns.ToString (), values.ToString ());
			insertCommand.CommandText = sql;
			return insertCommand;
		}

		private void CreateNewCommand (ref SqlCommand command)
		{
			SqlCommand sourceCommand = SourceCommand;
			if (command == null) {
				command = sourceCommand.Connection.CreateCommand ();
				command.CommandTimeout = sourceCommand.CommandTimeout;
				command.Transaction = sourceCommand.Transaction;
			}
			command.CommandType = CommandType.Text;
			command.UpdatedRowSource = UpdateRowSource.None;
			command.Parameters.Clear ();
		}

		private SqlCommand CreateUpdateCommand (bool useColumnsForParameterNames)
		{
			// If no table was found, then we can't do an update
			if (QuotedTableName == String.Empty)
				return null;

			CreateNewCommand (ref updateCommand);

			string command = String.Format ("UPDATE {0} SET ", QuotedTableName);
			StringBuilder columns = new StringBuilder ();
			StringBuilder whereClause = new StringBuilder ();
			int parmIndex = 1;
			bool keyFound = false;

			// First, create the X=Y list for UPDATE
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if (!IncludedInUpdate (schemaRow))
					continue;
				if (columns.Length > 0)
					columns.Append (" , ");

				SqlParameter parameter = null;
				if (useColumnsForParameterNames) {
					parameter = CreateParameter (schemaRow, false);
				} else {
					parameter = CreateParameter (parmIndex++, schemaRow);
				}
				updateCommand.Parameters.Add (parameter);
				ApplyParameterInfo (parameter, schemaRow, StatementType.Update, false);
				parameter.IsNullable = (bool) schemaRow ["AllowDBNull"];
				parameter.SourceVersion = DataRowVersion.Current;

				columns.Append (String.Format ("{0} = {1}", GetQuotedString (parameter.SourceColumn), parameter.ParameterName));
			}

			// Now, create the WHERE clause.  This may be optimizable, but it would be ugly to incorporate
			// into the loop above.  "Premature optimization is the root of all evil." -- Knuth
			foreach (DataRow schemaRow in dbSchemaTable.Rows) {
				if ((bool)schemaRow["IsExpression"] == true)
					continue;

				if (!IncludedInWhereClause (schemaRow)) 
					continue;

				if (whereClause.Length > 0) 
					whereClause.Append (" AND ");

				bool isKey = (bool) schemaRow ["IsKey"];
				SqlParameter parameter = null;

				if (isKey)
					keyFound = true;

				bool allowNull = (bool) schemaRow ["AllowDBNull"];
				if (!isKey) {
					string sourceColumnName = (string) schemaRow ["BaseColumnName"];
					if (useColumnsForParameterNames) {
						parameter = updateCommand.Parameters.Add (
							GetNullCheckParameterName (sourceColumnName),
							SqlDbType.Int);
					} else {
						parameter = updateCommand.Parameters.Add (
							GetParameterName (parmIndex++),
							SqlDbType.Int);
					}
					parameter.IsNullable = allowNull;
					parameter.SourceVersion = DataRowVersion.Current;
					parameter.Value = 1;
					
					whereClause.Append ("(");
					whereClause.Append (String.Format (clause1, parameter.ParameterName,
									GetQuotedString (sourceColumnName)));
					whereClause.Append (" OR ");
					
				}

				if (useColumnsForParameterNames) {
					parameter = CreateParameter (schemaRow, true);
				} else {
					parameter = CreateParameter (parmIndex++, schemaRow);
				}
				updateCommand.Parameters.Add (parameter);
				ApplyParameterInfo (parameter, schemaRow, StatementType.Update, true);
				parameter.IsNullable = allowNull;
				parameter.SourceVersion = DataRowVersion.Original;

				whereClause.Append (String.Format (clause2, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));

				if (!isKey)
					whereClause.Append (")");
			}
			if (!keyFound)
				throw new InvalidOperationException ("Dynamic SQL generation for the UpdateCommand is not supported against a SelectCommand that does not return any key column information.");

			// We're all done, so bring it on home
			string sql = String.Format ("{0}{1} WHERE ( {2} )", command, columns.ToString (), whereClause.ToString ());
			updateCommand.CommandText = sql;
			return updateCommand;
		}

		private SqlParameter CreateParameter (DataRow schemaRow, bool whereClause)
		{
			string sourceColumn = (string) schemaRow ["BaseColumnName"];
			string name;
			if (whereClause)
				name = GetParameterName ("Original_" + sourceColumn);
			else
				name = GetParameterName (sourceColumn);

			SqlParameter param = new SqlParameter ();
			param.ParameterName = name;
			param.SourceColumn = sourceColumn;
			return param;
		}

		private SqlParameter CreateParameter (int paramIndex, DataRow schemaRow)
		{
			string sourceColumn = (string) schemaRow ["BaseColumnName"];
			string name = GetParameterName (paramIndex);

			SqlParameter param = new SqlParameter ();
			param.ParameterName = name;
			param.SourceColumn = sourceColumn;
			return param;
		}
#endif // ONLY_1_1
				
		public static void DeriveParameters (SqlCommand command)
		{
			command.DeriveParameters ();
		}

#if NET_2_0
		new
#else
		protected override
#endif
		void Dispose (bool disposing)
		{
			if (!disposed) {
				if (disposing) {
#if ONLY_1_1
					if (insertCommand != null)
						insertCommand.Dispose ();
					if (deleteCommand != null)
						deleteCommand.Dispose ();
					if (updateCommand != null)
						updateCommand.Dispose ();
#endif
					if (dbSchemaTable != null)
						dbSchemaTable.Dispose ();
				}
				disposed = true;
			}
		}

		public
#if NET_2_0
		new
#endif // NET_2_0
		SqlCommand GetDeleteCommand ()
		{
#if NET_2_0 
			return (SqlCommand) base.GetDeleteCommand (false);
#else
			BuildCache (true);
			if (deleteCommand == null)
				return CreateDeleteCommand (false);
			return deleteCommand;
#endif
		}

		public
#if NET_2_0
		new
#endif // NET_2_0
		SqlCommand GetInsertCommand ()
		{
#if NET_2_0
			return (SqlCommand) base.GetInsertCommand (false);
#else
			BuildCache (true);
			if (insertCommand == null)
				return CreateInsertCommand (false);
			return insertCommand;
#endif
		}

		private string GetQuotedString (string value)
		{
			if (value == null || value.Length == 0)
				return value;

			string prefix = QuotePrefix;
			string suffix = QuoteSuffix;

			if (prefix.Length == 0 && suffix.Length == 0)
				return value;
			return String.Format ("{0}{1}{2}", prefix, value, suffix);
		}

		public 
#if NET_2_0
		new
#endif // NET_2_0
		SqlCommand GetUpdateCommand ()
		{
#if NET_2_0
			return (SqlCommand) base.GetUpdateCommand (false);
#else
			BuildCache (true);
			if (updateCommand == null)
				return CreateUpdateCommand (false);
			return updateCommand;
#endif
		}

#if NET_2_0
		public new SqlCommand GetUpdateCommand (bool useColumnsForParameterNames)
		{
			return (SqlCommand) base.GetUpdateCommand (useColumnsForParameterNames);
		}

		public new SqlCommand GetDeleteCommand (bool useColumnsForParameterNames)
		{
			return (SqlCommand) base.GetDeleteCommand (useColumnsForParameterNames);
		}

		public new SqlCommand GetInsertCommand (bool useColumnsForParameterNames)
		{
			return (SqlCommand) base.GetInsertCommand (useColumnsForParameterNames);
		}
		
		public override string QuoteIdentifier (string unquotedIdentifier)
		{
			if (unquotedIdentifier == null)
				throw new ArgumentNullException ("unquotedIdentifier");

			string prefix = QuotePrefix;
			string suffix = QuoteSuffix;

			if ((prefix == "[" && suffix != "]") || (prefix == "\"" && suffix != "\""))
				throw new ArgumentException ("The QuotePrefix " +
					"and QuoteSuffix properties do not match.");

			string escaped = unquotedIdentifier.Replace (suffix,
				suffix + suffix);
			return string.Concat (prefix, escaped, suffix);
		}
		
		public override string UnquoteIdentifier (string quotedIdentifier)
		{
			return base.UnquoteIdentifier (quotedIdentifier);
		}
#endif // NET_2_0

		private bool IncludedInInsert (DataRow schemaRow)
		{
			// If the parameter has one of these properties, then we don't include it in the insert:
			// AutoIncrement, Hidden, Expression, RowVersion, ReadOnly

			if (!schemaRow.IsNull ("IsAutoIncrement") && (bool) schemaRow ["IsAutoIncrement"])
				return false;
			if (!schemaRow.IsNull ("IsHidden") && (bool) schemaRow ["IsHidden"])
				return false;
			if (!schemaRow.IsNull ("IsExpression") && (bool) schemaRow ["IsExpression"])
				return false;
			if (!schemaRow.IsNull ("IsRowVersion") && (bool) schemaRow ["IsRowVersion"])
				return false;
			if (!schemaRow.IsNull ("IsReadOnly") && (bool) schemaRow ["IsReadOnly"])
				return false;
			return true;
		}

		private bool IncludedInUpdate (DataRow schemaRow)
		{
			// If the parameter has one of these properties, then we don't include it in the insert:
			// AutoIncrement, Hidden, RowVersion

			if (!schemaRow.IsNull ("IsAutoIncrement") && (bool) schemaRow ["IsAutoIncrement"])
				return false;
			if (!schemaRow.IsNull ("IsHidden") && (bool) schemaRow ["IsHidden"])
				return false;
			if (!schemaRow.IsNull ("IsRowVersion") && (bool) schemaRow ["IsRowVersion"])
				return false;
			if (!schemaRow.IsNull ("IsExpression") && (bool) schemaRow ["IsExpression"])
				return false;
			if (!schemaRow.IsNull ("IsReadOnly") && (bool) schemaRow ["IsReadOnly"])
				return false;

			return true;
		}

		private bool IncludedInWhereClause (DataRow schemaRow)
		{
			if ((bool) schemaRow ["IsLong"])
				return false;
			return true;
		}

		public
#if NET_2_0
		new
#endif
		void RefreshSchema ()
		{
			// FIXME: "Figure out what else needs to be cleaned up when we refresh."
			tableName = String.Empty;
			dbSchemaTable = null;
			base.RefreshSchema ();
#if ONLY_1_1
			deleteCommand = null;
			insertCommand = null;
			updateCommand = null;
#endif
		}

#if NET_2_0
		protected override void ApplyParameterInfo (DbParameter parameter,
		                                            DataRow datarow,
		                                            StatementType statementType,
		                                            bool whereClause)
		{
			SqlParameter sqlParam = (SqlParameter) parameter;
#else
		void ApplyParameterInfo (SqlParameter sqlParam,
		                         DataRow datarow,
		                         StatementType statementType,
		                         bool whereClause)
		{
#endif
			sqlParam.SqlDbType = (SqlDbType) datarow ["ProviderType"];

			object precision = datarow ["NumericPrecision"];
			if (precision != DBNull.Value) {
				short val = (short) precision;
				if (val < byte.MaxValue && val >= byte.MinValue)
					sqlParam.Precision = (byte) val;
			}

			object scale = datarow ["NumericScale"];
			if (scale != DBNull.Value) {
				short val = ((short) scale);
				if (val < byte.MaxValue && val >= byte.MinValue)
					sqlParam.Scale = (byte) val;
			}
		}

#if NET_2_0
		protected override
#endif
		string GetParameterName (int parameterOrdinal)
		{
			return String.Format ("@p{0}",  parameterOrdinal);
		}

#if NET_2_0
		protected override
#endif
		string GetParameterName (string parameterName)
		{
			return String.Format ("@{0}", parameterName);
		}

		string GetNullCheckParameterName (string parameterName)
		{
			return GetParameterName ("IsNull_" + parameterName);
		}

#if NET_2_0
		protected override string GetParameterPlaceholder (int parameterOrdinal)
		{
			return GetParameterName (parameterOrdinal);
		}
#endif

		#endregion // Methods

		#region Event Handlers

		private void RowUpdatingHandler (object sender, SqlRowUpdatingEventArgs args)
		{
			if (args.Command != null)
				return;
			try {
				switch (args.StatementType) {
				case StatementType.Insert:
					args.Command = GetInsertCommand ();
					break;
				case StatementType.Update:
					args.Command = GetUpdateCommand ();
					break;
				case StatementType.Delete:
					args.Command = GetDeleteCommand ();
					break;
				}
			} catch (Exception e) {
				args.Errors = e;
				args.Status = UpdateStatus.ErrorsOccurred;
			}
		}

#if NET_2_0
		protected override void SetRowUpdatingHandler (DbDataAdapter adapter)
		{
			if (!(adapter is SqlDataAdapter)) {
				throw new InvalidOperationException ("Adapter needs to be a SqlDataAdapter");
			}
			rowUpdatingHandler = new SqlRowUpdatingEventHandler (RowUpdatingHandler);
			((SqlDataAdapter) adapter).RowUpdating += rowUpdatingHandler;
		}

		protected override DataTable GetSchemaTable (DbCommand srcCommand)
		{
			using (SqlDataReader rdr = (SqlDataReader) srcCommand.ExecuteReader (CommandBehavior.KeyInfo | CommandBehavior.SchemaOnly))
				return rdr.GetSchemaTable ();
		}

		protected override DbCommand InitializeCommand (DbCommand command)
		{
			if (command == null) {
				command = new SqlCommand ();
			} else {
				command.CommandTimeout = 30;
				command.Transaction = null;
				command.CommandType = CommandType.Text;
				command.UpdatedRowSource = UpdateRowSource.None;
			}
			return command;
		}
#endif // NET_2_0

		#endregion // Event Handlers
	}
}