Bug 161191 Null is inserted when drag columns to query text with ctrl key pressed
Description: Null is inserted when drag columns to query text with ctrl key pressed Steps to reproduce: 1. New a data source. 2. New a dataset. 3. Press and hold ctrl key, select OFFICECODE and CITY columns, drag to query text. Expected result: "CLASSICMODELS.OFFICES.OFFICECODE,CLASSICMODELS.OFFICES.CITY" is inserted in query text. Actual result: "null,CLASSICMODELS.OFFICES.OFFICECODE,CLASSICMODELS.OFFICES.CITY" is inserted
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
item.setText( JdbcPlugin.getResourceString( "tablepage.refreshing" ) );
	}
	/**
	 * 
	 * @param item
	 */
	private void selectNode(TreeItem item)
	{
		TreeItem[] selectedItem = new TreeItem[1];
		selectedItem[0] = item;
		availableDbObjectsTree.setSelection(selectedItem);
		availableDbObjectsTree.setFocus();
	}
	/**
	 * @param schemaRs:
	 *            The ResultSet containing the List of schema
	 * @return A List of schema names
	 */
	private ArrayList getAllSchemaList( ResultSet schemaRs )
	{
		if ( schemaRs == null )
		{
			return null;
		}
		ArrayList allSchemas = new ArrayList( );
		try
		{
			while ( schemaRs.next( ) )
			{
				allSchemas.add( schemaRs.getString( "TABLE_SCHEM" ) );