# 配置数据库
app.config['SQLALCHEMY_DATABASE_URI'] = "mysql://root:mysql@127.0.0.1:3306/booktest"app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = Falsedb = SQLAlchemy(app)
class AddBookForm(FlaskForm): """自定义添加书籍的表单""" author = StringField('作者：', validators=[InputRequired('请输入作者')]) book = StringField('书名：', validators=[InputRequired('请输入书名')]) submit = SubmitField('添加') class Author(db.Model): """作者模型：一的一方""" __tablename__ = "authors" id = db.Column(db.Integer, primary_key=True) name = db.Column(db.String(64), unique=True)# 定义属性，以便作者模型可以直接通过该属性访问其多的一方的数据(书的数据)
# backref 给 Book 也添加了一个 author 的属性，可以通过 book.author 获取 book 所对应的作者信息 books = db.relationship('Book', backref='author') class Book(db.Model): """书的模型：多的一方""" __tablename__ = "books" id = db.Column(db.Integer, primary_key=True) name = db.Column(db.String(64), unique=True) # 记录一的一方的id作为外键 author_id = db.Column(db.Integer, db.ForeignKey(Author.id)) @app.route('/delete_author/<author_id>')def delete_author(author_id): """删除作者以及作者所有的书籍"""try:
author = Author.query.get(author_id) except Exception as e: print(e) return "查询错误"if not author:
return "作者不存在"# 删除作者及其所有书籍
try:
# 先删除书籍 Book.query.filter(Book.author_id == author_id).delete() # 再删除指定作者 db.session.delete(author) db.session.commit() except Exception as e: print(e) db.session.rollback() return "删除失败"return redirect(url_for('index'))
@app.route('/delete_book/<book_id>')def delete_book(book_id): """删除书籍""" try: book = Book.query.get(book_id) except Exception as e: print(e) return "查询错误"if not book:
return "书籍不存在"try:
db.session.delete(book) db.session.commit() except Exception as e: print(e) db.session.rollback() return '删除失败'return redirect(url_for('index'))
@app.route('/', methods=['get', 'post'])def index(): """返回首页"""book_form = AddBookForm()
# 如果book_form可以被提交
if book_form.validate_on_submit(): # 1. 取出表单中数据 author_name = book_form.author.data book_name = book_form.book.data# 2. 做具体业务逻辑代码实现
# 2.1 查询指定名字的作者 author = Author.query.filter(Author.name == author_name).first() # if 指定名字的作者不存在： if not author: try: # 添加作者信息到数据库 # 初始化作者的模型对象 author = Author(name=author_name) db.session.add(author) db.session.commit()# 添加书籍信息到数据库(指定其作者)
book = Book(name=book_name, author_id=author.id) db.session.add(book) db.session.commit() except Exception as e: db.session.rollback() print(e) flash("添加失败") else: book = Book.query.filter(Book.name == book_name).first()if not book:
try: # 添加书籍信息到数据库(指定其作者) book = Book(name=book_name, author_id=author.id) db.session.add(book) db.session.commit() except Exception as e: print(e) flash("添加失败") else: flash("已存在")else:
if request.method == "POST": flash('参数错误')# 1. 查询数据
authors = Author.query.all() # 2. 将数据传入到模板中进行渲染返回 return render_template('demo1_bookDemo.html', authors=authors, form=book_form)