public Map<String, Row> getAll(String tableName) throws DataBaseTableException {
        Map<String, Row> resultMap = new HashMap<String, Row>();
        for (DataBase db : databases.values()) {
            Map<String, Row> allInCurrentDB = db.getAll(tableName);

            for (String key : allInCurrentDB.keySet()) {
                Row row = allInCurrentDB.get(key);

                resultMap.put(key, row);
            }
        }
        return resultMap;
    }