Flask插件
flask-session
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下载
pip install Flask-session -
导入
from flask_session import Session -
实例化session
在__init__文件中
def create_app(): app = Flask(__name__) Session(app) return app -
配置文件
SESSION_TYPE = 'redis' -
用法和内置session一样
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实现原理
- 内置的session调用 session_interface = xxxx
- xxxx.open_session 解密cookie转化成字典给session
- xxxx.save_session 将session加密给cookie
- Flask-session 修改session_interface 制定的类
- 来改变session存储的位置
- 内置的session调用 session_interface = xxxx
SQLALchemy
创建连接
from sqlalchemy import create_engine
conn = create_engine(
# 'mysql+pymysql://rout用户:密码@连接地址:端口号/数据库名?charset=编码方式'
'mysql+pymysql://root:123@127.0.0.1:3306/day103?charset=ustf8',
max_overflow = 0, # 超过连接池大小外最多创建的连接数
pool_size = 5, # 连接池大小
pool_timeout=30, # 连接池中没有线程最多等待时间,否则报错
pool_recycle=-1, # 多久之后对连接池中的连接进行回收(重置), -1不回收
)
如何创建表
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导入
from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() -
单表创建
class Book(Base): __tablename__ = "book" id = Column(Integer, primary_key=True) title = Column(String(32), nullable=False，index=True) def __repr__(self): return self.title __table_args__ = ( # 联合唯一 UniqueConstraint("id", "title", name="uni_id_title"), # 联合索引 Index("id", "title") )from sqlalchemy import create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, Integer, String, DateTime from sqlalchemy import Index, UniqueConstraint import datetime # 连接数据库 ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",) # 实例化 Base = declarative_base() # 创建单表,继承Base class UserInfo(Base): __tablename__ = "user_info" id = Column(Integer, primary_key=True) name = Column(String(32), index=True, nullable=False) email = Column(String(32), unique=True) create_time = Column(DateTime, default=datetime.datetime.now) # 类似与django中的class Meta, 针对于本表 __table_args__ = ( # 设置联合唯一 UniqueConstraint("id", "name", name="uni_id_name"), # 设置联合索引 Index("name", "email") ) # 函数,方便创建表 def create_db(): Base.metadata.create_all(ENGINE) # 方便删除 def drop_db(): Base.metadata.drop_all(ENGINE) if __name__ == '__main__': # 执行 create_db() -
一对多表创建
class Book(Base): __tablename__ = "book" id = Column(Integer, primary_key=True) title = Column(String(32), nullable=False) publisher_id = Column(Integer, ForeignKey("publisher.id")) # 不生成字段建立关系 方便操作 # 一对多 publisher = relationship("Publisher", backref="books")from sqlalchemy import create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, Integer, String, DateTime from sqlalchemy import Index, UniqueConstraint, ForeignKey from sqlalchemy.orm import relationship import datetime ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",) Base = declarative_base() # ======一对多示例======= class UserInfo(Base): __tablename__ = "user_info" id = Column(Integer, primary_key=True) name = Column(String(32), index=True, nullable=False) email = Column(String(32), unique=True) create_time = Column(DateTime, default=datetime.datetime.now) # FK字段的建立 hobby_id = Column(Integer, ForeignKey("hobby.id")) # 不生成表结构 方便查询使用 hobby = relationship("Hobby", backref="user") __table_args__ = ( UniqueConstraint("id", "name", name="uni_id_name"), Index("name", "email") ) class Hobby(Base): __tablename__ = "hobby" id = Column(Integer, primary_key=True) title = Column(String(32), default="码代码") def create_db(): Base.metadata.create_all(ENGINE) def drop_db(): Base.metadata.drop_all(ENGINE) if __name__ == '__main__': create_db() # drop_db() -
多对对创建
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第三张表自己生成
class Book(Base): __tablename__ = "book" id = Column(Integer, primary_key=True) title = Column(String(32), nullable=False) publisher_id = Column(Integer, ForeignKey("publisher.id")) # 不生成字段建立关系 方便操作 # 一对多 publisher = relationship("Publisher", backref="books") # 多对多 tags = relationship("Tag", secondary="book2tag", backref="books") class Book2Tag(Base): __tablename__ = "book2tag" id = Column(Integer, primary_key=True) book_id = Column(Integer, ForeignKey("book.id")) tag_id = Column(Integer, ForeignKey("tag.id"))from sqlalchemy import create_engine from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Column, Integer, String, DateTime from sqlalchemy import Index, UniqueConstraint, ForeignKey from sqlalchemy.orm import relationship import datetime ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",) Base = declarative_base() # ======多对多示例======= class Book(Base): __tablename__ = "book" id = Column(Integer, primary_key=True) title = Column(String(32)) # 不生成表字段 仅用于查询方便 tags = relationship("Tag", secondary="book2tag", backref="books") class Tag(Base): __tablename__ = "tag" id = Column(Integer, primary_key=True) title = Column(String(32)) class Book2Tag(Base): __tablename__ = "book2tag" id = Column(Integer, primary_key=True) book_id = Column(Integer, ForeignKey("book.id")) tag_id = Column(Integer, ForeignKey("tag.id")) def create_db(): Base.metadata.create_all(ENGINE) def drop_db(): Base.metadata.drop_all(ENGINE) if __name__ == '__main__': create_db() # drop_db() -
创建表命令
Base.metadata.create_all(conn) # conn是连接池对象
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对数据库表的操作(增删改查)
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创建管理器
from sqlalchemy.orm import sessionmaker, scoped_session Session = sessionmaker(bind=conn) # 线程安全 根本本地线程会使用一个session session = scoped_session(Session)from sqlalchemy import create_engine from sqlalchemy.orm import sessionmaker, scoped_session from models_demo import Tag ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",) Session = sessionmaker(bind=ENGINE) # 每次执行数据库操作的时候，都需要创建一个session # 线程安全，基于本地线程实现每个线程用同一个session session = scoped_session(Session) # =======执行ORM操作========== tag_obj = Tag(title="SQLAlchemy") # 添加 session.add(tag_obj) # 提交 session.commit() # 关闭session session.close() -
基本增删改查
from sqlalchemy import create_engine from sqlalchemy.orm import sessionmaker, scoped_session from models_demo import Tag, UserInfo import threading ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",) Session = sessionmaker(bind=ENGINE) # 每次执行数据库操作的时候，都需要创建一个session session = Session() session = scoped_session(Session) # ============添加============ # tag_obj = Tag(title="SQLAlchemy") # # 添加 # session.add(tag_obj) # session.add_all([ # Tag(title="Python"), # Tag(title="Django"), # ]) # # 提交 # session.commit() # # 关闭session # session.close() # ============基础查询============ # ret1 = session.query(Tag).all() # ret2 = session.query(Tag).filter(Tag.title == "Python").all() # ret3 = session.query(Tag).filter_by(title="Python").all() # ret4 = session.query(Tag).filter_by(title="Python").first() # print(ret1, ret2, ret3, ret4) # ============删除=========== # session.query(Tag).filter_by(id=1).delete() # session.commit() # ===========修改=========== session.query(Tag).filter_by(id=22).update({Tag.title: "LOL"}) session.query(Tag).filter_by(id=23).update({"title": "王者毒药"}) session.query(Tag).filter_by(id=24).update({"title": Tag.title + "~"}, synchronize_session=False) # synchronize_session="evaluate" 默认值进行数字加减 session.commit() -
常用操作
# 条件查询 ret1 = session.query(Tag).filter_by(id=22).first() ret2 = session.query(Tag).filter(Tag.id > 1, Tag.title == "LOL").all() ret3 = session.query(Tag).filter(Tag.id.between(22, 24)).all() ret4 = session.query(Tag).filter(~Tag.id.in_([22, 24])).first() from sqlalchemy import and_, or_ ret5 = session.query(Tag).filter(and_(Tag.id > 1, Tag.title == "LOL")).first() ret6 = session.query(Tag).filter(or_(Tag.id > 1, Tag.title == "LOL")).first() ret7 = session.query(Tag).filter(or_( Tag.id>1, and_(Tag.id>3, Tag.title=="LOL") )).all() # 通配符 ret8 = session.query(Tag).filter(Tag.title.like("L%")).all() ret9 = session.query(Tag).filter(~Tag.title.like("L%")).all() # 限制 ret10 = session.query(Tag).filter(~Tag.title.like("L%")).all()[1:2] # 排序 ret11 = session.query(Tag).order_by(Tag.id.desc()).all() # 倒序 ret12 = session.query(Tag).order_by(Tag.id.asc()).all() # 正序 # 分组 ret13 = session.query(Tag.test).group_by(Tag.test).all() # 聚合函数 from sqlalchemy.sql import func ret14 = session.query( func.max(Tag.id), func.sum(Tag.test), func.min(Tag.id) ).group_by(Tag.title).having(func.max(Tag.id > 22)).all() # 连表 ret15 = session.query(UserInfo, Hobby).filter(UserInfo.hobby_id == Hobby.id).all() # print(ret15) 得到一个列表套元组 元组里是两个对象 ret16 = session.query(UserInfo).join(Hobby).all() # print(ret16) 得到列表里面是前一个对象 # 相当于inner join # for i in ret16: # # print(i[0].name, i[1].title) # print(i.hobby.title) ret17 = session.query(Hobby).join(UserInfo, isouter=True).all() ret17_1 = session.query(UserInfo).join(Hobby, isouter=True).all() ret18 = session.query(Hobby).outerjoin(UserInfo).all() ret18_1 = session.query(UserInfo).outerjoin(Hobby).all() # 相当于left join print(ret17) print(ret17_1) print(ret18) print(ret18_1) -
基于relationship的Fk
# 基于relationship的FK # 添加 user_obj = UserInfo(name="提莫", hobby=Hobby(title="种蘑菇")) session.add(user_obj) hobby = Hobby(title="弹奏一曲") hobby.user = [UserInfo(name="琴女"), UserInfo(name="妹纸")] session.add(hobby) session.commit() # 基于relationship的正向查询 user_obj_1 = session.query(UserInfo).first() print(user_obj_1.name) print(user_obj_1.hobby.title) # 基于relationship的反向查询 hb = session.query(Hobby).first() print(hb.title) for i in hb.user: print(i.name) session.close() -
基于relationship的M2M
# 添加 book_obj = Book(title="Python源码剖析") tag_obj = Tag(title="Python") b2t = Book2Tag(book_id=book_obj.id, tag_id=tag_obj.id) session.add_all([ book_obj, tag_obj, b2t, ]) session.commit() # 上面有坑哦~~~~ book = Book(title="测试") book.tags = [Tag(title="测试标签1"), Tag(title="测试标签2")] session.add(book) session.commit() tag = Tag(title="LOL") tag.books = [Book(title="大龙刷新时间"), Book(title="小龙刷新时间")] session.add(tag) session.commit() # 基于relationship的正向查询 book_obj = session.query(Book).filter_by(id=4).first() print(book_obj.title) print(book_obj.tags) # 基于relationship的反向查询 tag_obj = session.query(Tag).first() print(tag_obj.title) print(tag_obj.books)
Flask_Script
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下载
pip install flask-script -
导入
from flask_demo import create_app from flask_script import Manager -
实例化
app = create_app() # 实例化 manager = Manager(app) if __name__ == '__main__': # app.run() manager.run() -
自定义的命令
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位置传参
@manager.command def mycommad(arg): prin(arg) # python manange.py my_command 123 -
关键字
@manager.option('-n','--name', dest='name') @manager.option('-u','--url', dest='url') def cmd(name, url): print(name, url) # python manager.py cmd -n xiatian -u www.xxx
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Flask-Migrate
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!!! 依赖flask-script
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下载
pip install flask-migrate -
导入
from flask_Migrate import Migrate, MigrateCommand -
实例化
Migrate(app) manager.add_command('db', MigrateCommand) """ python manager.py db init python manager.py db migrate # 类型于makemigrations python manager.py db uprade # migrate """