I have a table model in a flask application:

```
class Article(db.Model):
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    title = db.Column(db.String(80), nullable=False)
    body = db.Column(db.Text, nullable=False)
    pubDate = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now())

```

And I use `db.crate_all()` and `db.add()`/`db.session` to add some data to the above table, work well!

Then I want to update and add some properties of class Article:

```
class Article(db.Model):
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    title = db.Column(db.String(80), nullable=False)
    body = db.Column(db.Text, nullable=False)
    createDate = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now())
    touchDate = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now())
    publishDate = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now())
    isVisible = db.Column(db.Boolean, nullable=False, default=True)
    isDraft = db.Column(db.Boolean, nullable=False, default=True)

```

After I update the class Article, I use `db.create_all()` again. When I run my flask application, I got following error message:

```
cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such column: article.createDate
[SQL: SELECT article.id AS article_id, article.title AS article_title, article.body AS article_body, article."createDate" AS "article_createDate", article."touchDate" AS "article_touchDate", article."publishDate" AS "article_publishDate", article."isVisible" AS "article_isVisible", article."isDraft" AS "article_isDraft" 
FROM article 
WHERE article."isVisible" = 1]

```

Whenever I change the `db.Model` subclass, does the table in database sync automatically? What operation is needed after the properties of `db.Model` subclass change?