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
* 
	 * @param schemaName
	 * @return
	 */
	private boolean containsTableInSchema( String schemaName )
	{
		ResultSet rs = metaDataProvider.getAlltables( metaDataProvider.getCatalog( ),
				schemaName,
				"%",
				new String[]{
						"TABLE", "VIEW"
				} );
		boolean hasNonSystemTable = false;
		if ( rs != null )
		{
			try
			{
				while ( rs.next( ) )
				{
					if ( !"SYSTEM TABLE".equalsIgnoreCase( rs.getString( "TABLE_TYPE" ) ) )
					{
						hasNonSystemTable = true;
						break;
					}
				}
			}
			catch ( SQLException e )
			{
				e.printStackTrace( );
			}