public Vector<String> getTables() {
        String TABLE_NAME = "TABLE_NAME";
        String TABLE_SCHEMA = "TABLE_SCHEM";
        String[] TABLE_TYPES = {"TABLE"};        
        
        Vector<String> tables = new Vector<String>();
        
          // Verbindung zur Datenbank, Auslese Variablen
        Statement  st = null;
        ResultSet  rs = null;

        try {
          DatabaseMetaData dbmd = conn.getMetaData();
          rs = dbmd.getTables(null, null, null, TABLE_TYPES);
          
         while (rs.next()) {
             // System.out.println(rs.getString(TABLE_NAME));
             // System.out.println(rs.getString(TABLE_SCHEMA));
            tables.add( rs.getString(TABLE_NAME) );
         }
    

        } catch( Exception ex ) {
          System.out.println( ex );
        } finally {
          try { if( null != rs ) rs.close(); } catch( Exception ex ) {}
          try { if( null != st ) st.close(); } catch( Exception ex ) {}          
        }  
        return tables;
    }
    
    
    public Vector<TableColumns> getColumns(String tablename) {
        TableColumns tc;
        Vector<TableColumns> liste = new Vector<TableColumns>();
        String sql = "SELECT column_name, Data_type FROM INFORMATION_SCHEMA.COLUMNS\n" +
                    "where table_name='"+ tablename+"' ";
        DataTable dt1 = selectDBS(sql);
        ArrayList<ArrayList> tableRows = dt1.tableRows;
        ArrayList<String> tupels;            
        for (int row = 0; row < tableRows.size(); row++) {
            tupels = tableRows.get(row);
            tc = new TableColumns();
            tc.column_name = tupels.get(0);
            tc.data_type = tupels.get(1);
            liste.add(tc);
        }                
        return liste;        
    }