@app.route('/') def index(): data_all_new = [] data_all_down = [] marine_organisms = Organism_data.query.order_by('id').all() marine_hydrologys = Hydrology_data.query.order_by('id').all() marine_chemistrys = Chemistry_data.query.order_by('id').all() data_all_new = data_all_new + marine_hydrologys data_all_new = data_all_new + marine_organisms data_all_new = data_all_new + marine_chemistrys data_all_down = data_all_new.copy() cmpfun_new = operator.attrgetter('data_time') n_new, reverse=True)cmpfun_down = operator.attrgetter('down_time') data_all_down.sort(key=cmpfun_down, reverse=True) articles = Article.query.order_by('time').limit(5).all() context = { 'banners': Banner.query.order_by('id').all(), 'data_all_new': data_all_new, 'data_all_down': data_all_down, 'articles': articles } return render_template('index.html', **context)类图怎么画

在这段代码中，没有定义任何类，只有使用了已经定义好的模型类。因此，类图只需要展示这三个模型类即可。

下面是一个简单的UML类图示例，其中包含了三个模型类Organism_data、Hydrology_data和Chemistry_data：

+------------------+        +------------------+        +------------------+
| Organism_data    |        | Hydrology_data   |        | Chemistry_data   |
+------------------+        +------------------+        +------------------+
| id               |        | id               |        | id               |
| data_name        |        | data_name        |        | data_name        |
| data_time        |        | data_time        |        | data_time        |
| data_file        |        | data_file        |        | data_file        |
+------------------+        +------------------+        +------------------+

这个类图中，每个模型类都包含了四个属性：id、data_name、data_time和data_file。这些属性对应了每个数据表中的字段。