Flask框架(2)之Flask的模型的创建和对应关系

Flask的使用

• 模型的创建,在项目下创建models.py,并输入

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime

app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = "mysql+pymysql://root:123456@localhost:3306/pymysqls"
# 如果设置成 True (默认情况)，Flask-SQLAlchemy 将会追踪对象的修改并且发送信号。
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = True

# 绑定app至SQLAlchemy
db = SQLAlchemy(app)

#会员模型
class User(db.Model):
  # __tablename__ = 'user'
  id = db.Column(db.Integer,primary_key=True)
  name = db.Column(db.String(100),unique=True)
  pwd= db.Column(db.String(100))
  email= db.Column(db.String(100))
  phone= db.Column(db.String(11))
  info= db.Column(db.Text)
  face = db.Column(db.String(255))
  addtime = db.Column(db.DateTime,default=datetime.now)

class Stu(db.Model):
  id = db.Column(db.Integer,primary_key=True)
  sname = db.Column(db.String(10))
  email = db.Column(db.String(50))
  age = db.Column(db.Integer)

if __name__ == "__main__":
  db.create_all()

• 模型的操作,在项目下的models.py文件输入

# # 查询数据
# res = User.query.all()
# print(res)
# print(res[0].name)
# print(res[0].email)

# 添加
# s = Stu()
# s.sname = '张三'
# s.email = 'zs@qq.com'
# s.age = 22
# db.session.add(s)
# db.session.commit()
# 添加
# data = {'sname':'lisi','email':'ls@qq.com','age':20}
# s = Stu(**data)
# db.session.add(s)
# db.session.commit()

# 删除
# # 先获取对象
# ob = Stu.query.get(2)
# # print(ob.sname)
# db.session.delete(ob)
# db.session.commit()

# 修改
# ob = Stu.query.get(1)
# ob.sname = 'zhangsansa'
# db.session.add(ob)
# db.session.commit()

# 查询
  # all() [<Stu 3>] 获取所有
  # get() 获取一个指定对象 通过主键查询
  # first()  <Stu 3>

  # filter_by
  # res = Stu.query.filter_by(sname='lisisi').first()

  # 获取不到数据,则返回404
  # res = Stu.query.get_or_404(7)

  # res = Stu.query.filter(Stu.email.endswith('@qq.com')).all()
  # res = Stu.query.filter(Stu.email.startswith('l')).all()

  # res = Stu.query.limit(2).all()
  # 跳过两条取两条 (limit 2,2)
  # res = Stu.query.limit(2).offset(2).all()
  # print(res)

• 一对一(one-to-one)关系,在项目下创建modelsORM.py,并输入

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from datetime import datetime

app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = "mysql+pymysql://root:123456@127.0.0.1:3306/myapp"
# 如果设置成 True (默认情况)，Flask-SQLAlchemy 将会追踪对象的修改并且发送信号。
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = True

# 绑定app至SQLAlchemy
db = SQLAlchemy(app)

class Users(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  name = db.Column(db.String(50))
  userinfo = db.relationship('UserInfo', backref='usersa', cascade="all, delete,delete-orphan",uselist=False)

class UserInfo(db.Model):
  id = db.Column(db.Integer, primary_key=True)
  email = db.Column(db.String(50))
  users_id = db.Column(db.Integer, db.ForeignKey('users.id'))

if __name__ == "__main__":
    db.create_all()

  # 添加数据
    # 创建用户
    # u = Users(name = '赵六')
    # db.session.add(u)
    # db.session.commit()

    # # 创建用户详情
    # ui = UserInfo(email = 'zl@qq.com',users_id = u.id)
    # db.session.add(ui)
    # db.session.commit()

  # 查询
    # 通过用户 获取详情信息
    # u = Users.query.first()
    # print(u.name)
    # print(u.userinfo.email)

    # 通过用户详情 获取用户数据
    # ui = UserInfo.query.first()
    # print(ui.email)
    # print(ui.users_id)
    # print(ui.usersa.name)

  # 删除
    # u = Users.query.first()
    # db.session.delete(u)
    # db.session.commit()

• 一对多(one-to-many)关系,在项目下的modelsORM.py文件输入

#分类
class Types(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    goodsa = db.relationship('Goods',backref="goodsb")
    # stus = db.relationship('Stus',backref="classs",cascade="all, delete,delete-orphan")
    # def __repr__(self):
    #     return '<Classs %r>' % self.cname
# 商品
class Goods(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(50))
    types_id = db.Column(db.Integer, db.ForeignKey('types.id'))
    # def __repr__(self):
    #     return '<Stus %r>' % self.uname

# 一对多关系
# t = Types(name='手机')
# db.session.add(t)
# db.session.commit()

# g1 = Goods(title='魅族手机',types_id=t.id)
# g2 = Goods(title='小米手机',types_id=t.id)
# db.session.add(g1)
# db.session.add(g2)
# db.session.commit()

# 通过 分类 获取商品
# t = Types.query.first()
# print(t.name)
# print(t.goodsa)

# 通过商品 获取 分类
# g = Goods.query.first()
# print(g.title)
# print(g.goodsb.name)

# 删除
t = Types.query.first()
db.session.delete(t)
db.session.commit()

• 多对多(many-to-many)关系,在项目下的modelsORM.py文件输入

tags = db.Table('post_tag',
    db.Column('tag_id', db.Integer, db.ForeignKey('tags.id')),
    db.Column('post_id', db.Integer, db.ForeignKey('posts.id'))
)
#文章
class Posts(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(255))
    tags = db.relationship('Tags',secondary=tags,backref='Posts')
#标签
class Tags(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    # def __repr__(self):
    #     return self.name

# # 创建文章
# p1=Posts(title='flask开发')
# p2=Posts(title='django开发')
# p3=Posts(title='web框架开发博客系统')

# # 创建标签
# t1=Tags(name='falsk')
# t2=Tags(name='django')
# t3=Tags(name='web框架')

# # 添加数据
# p1.tags = [t1,t3]
# p2.tags = [t2,t3]
# p3.tags = [t3]

# db.session.add(p1)
# db.session.add(p2)
# db.session.add(p3)
# db.session.commit()

# 根据文章查标签
# p = db.session.query(Posts).first()
# print(p)
# print(p.title)
# print(p.tags)

# 根据标签查文章
# t = db.session.query(Tags).get(7)
# print(t)
# print(t.name)
# print(t.Posts)