// Add this as last function in datadict-mssqlnative.inc.php or datadict-mssql.inc.php

	function DropDefaultValue($tabname, $fieldname)
	{
		$strSql = "";
		
		// delete default value if exists
		if( $this->connection->IsConnected() )
		{
			$oRs = $this->connection->Execute('

						SELECT name FROM sysobjects so JOIN sysconstraints sc ON so.id = sc.constid
						WHERE object_name(so.parent_obj) = \'' . $tabname . '\'
						AND so.xtype = \'D\'
						AND sc.colid = (
							SELECT colid FROM syscolumns
							WHERE id = object_id(\'' . $tabname . '\') AND name = \'' . $fieldname . '\'
						)
			');
			if( $oRs )
				if(!$oRs->EOF) 
				{
					$defName = $oRs->fields[0];
					// Remove default value
					$strSql = "ALTER TABLE $tabname DROP CONSTRAINT $defName";
				}
			
			$oRs->Close();
		};
		//echo "<br>DropDefaultValue: " . $strSql . "<br>";
		
		return $strSql;
	}


// Change those methods

	function AlterColumnSQL($tabname, $flds)
	{
		$tabname = $this->TableName($tabname);
		$sql = array();
		list($lines,$pkey) = $this->_GenFields($flds);

		foreach($lines as $v) {

			// get field name and type
			$arTmp = array();
			$arTmp = preg_split("/[\s]+/", $v);
			$arCnt = count($arTmp);
			$fieldname = $arTmp[0];
			$fieldtype = $arTmp[1];

			$bHasDef = false;
			$bIsNull = true;
			
			for($i = 2; $i < $arCnt; $i++) {
				// get default value
				if( trim($arTmp[$i]) == "DEFAULT" ) 
				{
					$bHasDef = true;
					if( $i+1 <= $arCnt ) {
						$field_def = $arTmp[$i+1];
					}
				}
				
				// get nullability
				if( trim($arTmp[$i]) == "NOTNULL" )
					$bIsNull = false;
			}
			

			// delete default value if exists
			$strDropDef = $this->DropDefaultValue($tabname, $fieldname);
			if( trim($strDropDef) !== "" )
				$sql[] = $strDropDef;


			if($bHasDef) {				
				// change type and nulls
				if($bIsNull)
					$sql[] = "ALTER TABLE $tabname $this->alterCol $fieldname $fieldtype NOT NULL";
				else
					$sql[] = "ALTER TABLE $tabname$this->alterCol $fieldname $fieldtype";
				// Add default value
				$sql[] = "ALTER TABLE $tabname ADD CONSTRAINT def_" . $tabname . "_" . $fieldname . " DEFAULT " . $field_def . " FOR $fieldname";
			}
			else {
				$sql[] = "ALTER TABLE $tabname $this->alterCol $v";
			}
		}		
/*		
		echo "<pre>";
		print_r($sql);
		echo "</pre><br>";
*/
		return $sql;
	}


	
	function DropColumnSQL($tabname, $flds)
	{
		$tabname = $this->TableName ($tabname);
		if (!is_array($flds))
			$flds = explode(',',$flds);
		$f = array();
		$s = 'ALTER TABLE ' . $tabname;
		foreach($flds as $v) {
			
			// delete default value if exists
			$strDropDef = $this->DropDefaultValue($tabname, $v);
			if( trim($strDropDef) !== "" )
				$sql[] = $strDropDef;

			
			$f[] = "\n$this->dropCol ".$this->NameQuote($v);
		}
		$s .= implode(', ',$f);
		$sql[] = $s;
/*	
		echo "<pre>";
		print_r($sql);
		echo "</pre><br>";
*/
		return $sql;
	}