from flask import Flask,render_template,flash,request,redirect,url_for from flask_sqlalchemy import SQLAlchemy from flask_wtf import FlaskForm #定义表单 from wtforms import StringField,SubmitField,IntegerField from wtforms.validators import DataRequired app = Flask(__name__) #数据库配置 app.secret_key = 'csdnblog' app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://root:wanyanfei123@localhost:3306/library' app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False db = SQLAlchemy(app) #作者模型 class Author(db.Model): __tablename__ = 'authors' id = db.Column(db.Integer, primary_key=True)#主键 author_name = db.Column(db.String(16), unique=True) #关系引用 books = db.relationship('Book', backref='author') #反向关联,查询books表,返回books—-obj, # books-obj。author找到books外键关联数据 #查books返回authors # def __repr__(self): # return 'Author :%s' % self.name #货物 class Goods(db.Model): __tablename__ = 'goods' id = db.Column(db.Integer, primary_key=True) # 主键 Goods_id = db.Column(db.Integer,db.ForeignKey('books.id')) #def __repr__(self): # return 'Goods :%s' % self.name #出版社 class Press(db.Model): __tablename__ = 'press' id = db.Column(db.Integer, primary_key=True)#主键 press_name = db.Column(db.String(16), unique=True) #def __repr__(self): # return 'Press :%s' % self.name #语言 class Language(db.Model): __tablename__ = 'language' id = db.Column(db.Integer, primary_key=True)#主键 language_name = db.Column(db.String(16), unique=True) # def __repr__(self): # return 'Language :%s' % self.name #类型 class Category(db.Model): __tablename__ = 'category' id = db.Column(db.Integer, primary_key=True)#主键 category_name = db.Column(db.String(16), unique=True) # def __repr__(self): # return 'Category :%s' % self.name #书籍模型 class Book(db.Model): __tablename__ = 'books' name = db.Column(db.String(16), unique=True) time = db.Column(db.String(16), unique=True) id = db.Column(db.Integer, primary_key=True)# 主键 value = db.Column(db.Integer, unique=True) number = db.Column(db.Integer, unique=True) #unique=True表示重复出现的记录只保存一条 author_id = db.Column(db.Integer,db.ForeignKey('authors.id')) Press_id = db.Column(db.Integer, db.ForeignKey('press.id')) Language_id = db.Column(db.Integer, db.ForeignKey('language.id')) Category_id = db.Column(db.Integer, db.ForeignKey('cagetory.id')) #authors = db.relationship('Author',backref='author') #传入表单 class Aform(FlaskForm): #flash('添加书籍') book = StringField('书名', validators=[DataRequired()]) press_time = StringField('出版时间') value = IntegerField('价格', validators=[DataRequired()]) num = IntegerField('数量', validators=[DataRequired()]) author_name = StringField('作者', validators=[DataRequired()]) # bookid = StringField('自定义书号', validators=[DataRequired()]) language = StringField('语言', validators=[DataRequired()]) press = StringField('出版社', validators=[DataRequired()]) category = StringField('类别', validators=[DataRequired()]) #validators=[DataRequired()]对于用户提交的数据进行验证,是否为空 #在此对应用户id和书籍id submit = SubmitField('提交') @app.route('/delete_author/<author_id>') def delete_author(author_id): author = Author.query.get(author_id) #get(),参数为主键,如果主键不存在没有返回内容,返回主键键值对象 if author: try: Book.query.filter_by(author_id = author.id).delete() #删除某作者和他的书 #查询Book副键对应的实例,然后删掉 db.session.delete(author) db.session.commit() except Exception as e: print(e) flash('删除作者失败') db.session.rollback() #数据库会话回滚, # 通过db.session.rollback()方法, # 实现会话提交数据前的状态 else: flash('作者没找到') return redirect(url_for('index')) # @app.route('/delete_book/<book_id>') def delete_book(book_id): #查询是否存在该ID的书 book= Book.query.get(book_id) #如果有就删除 if book: try: db.session.delete(book) db.session.commit() except Exception as e: print(e) flash('删除书籍失败') db.session.rollback() else: #书籍不存在提示错误 flash('书籍没有找到') #url_for传入视图函数名,返回该视图函数对应的路由地址 #redirect(),功能就是跳转到指定的url return redirect(url_for('index')) @app.route('/',methods = ['POST','GET']) #这个url地址允许 POST与GET 请求两种方式, # 是个列表也就是意味着可以允许多重请求方式, # 这里表单提交需要通过GET显示HTML页面,再通过POST提交数据 def index(): form = Aform() #表单对象author_form #调用WTF函数实现验证 if form.validate_on_submit(): #验证通过获取数据1.查看表单必填数据是否为空: # validators=[DataRequired()],如果不写这句, # form.validate_on_submit()就认为表单是空的,所以会false aut = Author.query.filter_by(author_name = form.author_name.data).first() lan = Language.query.filter_by(language_name = form.language.data).first() pre = Press.query.filter_by(press_name = form.press.data).first() cat = Category.query.filter_by(category_name = form.category.data).first() if not aut: a = Author( name = form.author_name.data ) db.session.add(a) Book(id = a.id) db.session.commit() if not lan: l = Language( name = form.language.data ) db.session.add(l) Book(id=l.id) db.session.commit() if not pre: p = Press( name = form.press.data ) db.session.add(p) Book(id=p.id) db.session.commit() if not cat: c = Category( name = form.category.data ) db.session.add(c) Book(id=c.id) db.session.commit() #if aut and lan and pre and cat: newform = Book( name = form.book.data, time = form.press_time.data, value = form.value.data, number = form.num.data, author_id = aut.id, Category_id = cat.id, Press_id = pre.id, Language_id = lan.id ) db.session.add(newform) Book(id = newform.id) db.session.commit() goods = Goods( Goods_id = newform.id ) db.session.add(newform) Book(id = goods.id) db.session.commit() return render_template('books.html', form = form) #返回模板渲染 if __name__ == '__main__': db.drop_all() # 删除表 db.create_all() # 创建表 #往Author表里插数据 au1 = Author(author_name='老王', id = 1111) au2 = Author(author_name='老宋', id = 2222) au3 = Author(author_name='老刘', id = 3333) db.session.add_all([au1, au2, au3]) db.session.commit() c1 = Category(category_name = '计算机' , id = 6345) c2 = Category(category_name = '心理学' , id = 6745) c3 = Category(category_name = '社会学' , id = 6455) c4 = Category(category_name = '哲学' , id = 7465) db.session.add_all([c1, c2, c3, c4]) db.session.commit() l1 = Language(language_name = 'chinese' , id = 7483) l2 = Language(language_name = 'English' , id = 7848) l3 = Language(language_name = 'Russian' , id = 5236) l4 = Language(language_name = 'Latin' , id = 9484) db.session.add_all([l1, l2, l3, l4]) db.session.commit() p1 = Press(press_name = '机械工业出版社' , id = 8475) p2 = Press(press_name = '人民文学出版社' , id = 4657) p3 = Press(press_name = '新华出版社' , id = 2949) p4 = Press(press_name = '人民邮电出版社' , id = 8375) db.session.add_all([p1, p2, p3, p4]) db.session.commit() bk1 = Book(name='老王回忆录', time = '2020-8-29', value = 120,number = 1, author_id = au1.id, Category_id = c1.id, Press_id = p1.id, Language_id = l1.id ) bk2 = Book(name='我读书少你别骗我', time = '2020-7-29', value = 130,number = 1,author_id = au1.id,Category_id = c2.id, Press_id = p3.id, Language_id = l3.id) bk3 = Book(name='如何征服美丽少女', time = '2020-6-29', value = 140,number = 1,author_id = au2.id,Category_id = c1.id, Press_id = p4.id, Language_id = l4.id) bk4 = Book(name='如何征服美丽少男', time = '2020-6-29', value = 150,number = 1, author_id = au2.id,Category_id = c4.id, Press_id = p1.id, Language_id = l1.id) bk5 = Book(name='如何使自己变得更骚', time = '2020-6-29', value = 160,number = 1,author_id = au3.id,Category_id = c3.id, Press_id = p3.id, Language_id = l2.id) bk6 = Book(name='我变秃了,也变强了', time = '2020-6-29', value = 170,number = 1,author_id = au3.id,Category_id = c1.id, Press_id = p2.id, Language_id = l3.id) #往附表books里插数据,附表的外键 = 主表的主键 db.session.add_all([bk1, bk2, bk3, bk4, bk5, bk6]) bk1 = Book(id = bk1.id) bk2 = Book(id = bk2.id) bk3 = Book(id = bk3.id) bk4 = Book(id = bk4.id) bk5 = Book(id = bk5.id) bk6 = Book(id = bk6.id) db.session.commit() #库存 g1 = Goods( Goods_id = bk1.id) g2 = Goods(id = 664, Goods_id = bk2.id) g3 = Goods(id = 437, Goods_id = bk3.id) g4 = Goods(id = 765, Goods_id = bk4.id) g5 = Goods(id = 565, Goods_id = bk5.id) g6 = Goods(id = 535, Goods_id = bk6.id) g7 = Goods(id = 356, Goods_id = bk6.id) g8 = Goods(id = 665, Goods_id = bk5.id) g9 = Goods(id = 855, Goods_id = bk5.id) db.session.add_all([g1, g2, g3, g4, g5, g6,g7,g8,g9]) g1 = Goods(id = g1.id) db.session.commit() app.run(debug = True)
报错:
Traceback (most recent call last):
File "D:/xx/pythonProject/mysql3.py", line 198, in <module>
db.drop_all() # 删除表
File "C:\Users\wan\anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py", line 1102, in drop_all
self._execute_for_all_tables(app, bind, 'drop_all')
File "C:\Users\wan\anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py", line 1086, in _execute_for_all_tables
op(bind=self.get_engine(app, bind), **extra)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 4572, in drop_all
bind._run_visitor(
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 2098, in _run_visitor
conn._run_visitor(visitorcallable, element, **kwargs)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1657, in _run_visitor
visitorcallable(self.dialect, self, **kwargs).traverse_single(element)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\visitors.py", line 144, in traverse_single
return meth(obj, **kw)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\ddl.py", line 892, in visit_metadata
sort_tables_and_constraints(
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\ddl.py", line 1193, in sort_tables_and_constraints
dependent_on = fkc.referred_table
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 3420, in referred_table
return self.elements[0].column.table
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\util\langhelpers.py", line 883, in __get__
obj.__dict__[self.__name__] = result = self.fget(obj)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2138, in column
raise exc.NoReferencedTableError(
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'books.Category_id' could not find table 'cagetory' with which to generate a foreign key to target column 'id'
File "D:/xx/pythonProject/mysql3.py", line 198, in <module>
db.drop_all() # 删除表
File "C:\Users\wan\anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py", line 1102, in drop_all
self._execute_for_all_tables(app, bind, 'drop_all')
File "C:\Users\wan\anaconda3\lib\site-packages\flask_sqlalchemy\__init__.py", line 1086, in _execute_for_all_tables
op(bind=self.get_engine(app, bind), **extra)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 4572, in drop_all
bind._run_visitor(
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 2098, in _run_visitor
conn._run_visitor(visitorcallable, element, **kwargs)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\engine\base.py", line 1657, in _run_visitor
visitorcallable(self.dialect, self, **kwargs).traverse_single(element)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\visitors.py", line 144, in traverse_single
return meth(obj, **kw)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\ddl.py", line 892, in visit_metadata
sort_tables_and_constraints(
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\ddl.py", line 1193, in sort_tables_and_constraints
dependent_on = fkc.referred_table
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 3420, in referred_table
return self.elements[0].column.table
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\util\langhelpers.py", line 883, in __get__
obj.__dict__[self.__name__] = result = self.fget(obj)
File "C:\Users\wan\anaconda3\lib\site-packages\sqlalchemy\sql\schema.py", line 2138, in column
raise exc.NoReferencedTableError(
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'books.Category_id' could not find table 'cagetory' with which to generate a foreign key to target column 'id'
前几个表单都可以关联,就Book不行
明明是最简单的开发项目,copy了别人代码,写了好几天还被bug卡住了,大一菜鸟,希望有大佬可以帮我改改😭😭
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