System.Data.SqlClient.SqlCommandBuilder.CreateUpdateCommand C# (CSharp) Method

		private SqlCommand CreateUpdateCommand (DataRow row, DataTableMapping tableMapping) 
		{
			// 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;
			string dsColumnName = String.Empty;
			bool keyFound = false;

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

				SqlParameter parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));

				dsColumnName = tableMapping.ColumnMappings [parameter.SourceColumn].DataSetColumn;
				if (row != null)
					parameter.Value = row [dsColumnName, DataRowVersion.Proposed];

				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 (!IncludedInWhereClause (schemaRow)) 
					continue;

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

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


				if (!isKey) {
					parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));

					dsColumnName = tableMapping.ColumnMappings [parameter.SourceColumn].DataSetColumn;
					if (row != null)
						parameter.Value = row [dsColumnName];

					whereClause.Append ("(");
					whereClause.Append (String.Format (clause1, GetQuotedString (parameter.SourceColumn), parameter.ParameterName));
					whereClause.Append (" OR ");
				}
				else
					keyFound = true;
					
				parameter = updateCommand.Parameters.Add (CreateParameter (parmIndex++, schemaRow));

				dsColumnName = tableMapping.ColumnMappings [parameter.SourceColumn].DataSetColumn;
				if (row != null)
					parameter.Value = row [dsColumnName];

				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;
		}