一.安装(稳定版的1.2.17)

二.一般使用(切记切记不要使用模块的名字作为项目名字,否则会出现玄学解决不了的问题------坑)

#.导入SQLALchemy

from  sqlalchemy.ext.declarative import declarative_base

#.创建ORM模型基类

Base = declarative_base()

#.导入ORM对应数据类型的字段

from sqlalchemy import Column,Integer,String

#.创建ORM对象

class User(Base):

    __tablename__ ="user"                  #创建表名字

    id = Column(Integer,primary_key=True,autoincrement=True)  #创建id主键自增长

    name = Column(String(),index=True)

#5创建数据库链接

from sqlalchemy import create_engine

engine = create_engine("mysql+pymysql://root:@127.0.0.1:3306/day127?charset=utf8")

#6去数据库中创建与User所对应的数据库

Base.metadata.create_all(engine)

三.创建外键关联

from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

from sqlalchemy import Column,String,ForeignKey,Integer

from sqlalchemy.orm import relationship

class Student(Base):

    __tablename__ ="student"

    id = Column(Integer,primary_key=True)

    name = Column(String())

    school_id = Column(Integer,ForeignKey("school.id"))

    stu2sch = relationship("School",backref="sch2stu")

class School(Base):

    __tablename__="school"

    id = Column(Integer,primary_key=True)

    name = Column(String())

from sqlalchemy import create_engine

engine = create_engine("mysql+pymysql://root:@127.0.0.1:3306/127?charset=utf8")

Base.metadata.create_all(engine)

四.增加数据

# 通过SQLAlchemy对数据表进行增删改查

# crud == 增删改查

# 想要操纵数据库 打开数据库连接

# from sqlalchemy import create_engine

# engine = create_engine("mysql+pymysql://root:@127.0.0.1:3306/day127?charset=utf8")

from create_table import engine

# 创建会话 - 打开数据库连接

from sqlalchemy.orm import sessionmaker

# 创建会话窗口

Session = sessionmaker(engine)

# 打开会话窗口

db_session = Session()

# .增加数据 == insert

# # insert into user(name) values("DragonFire")

# from create_table import User

# user_obj = User(name="Ywb")

# # 通过db_session已经打开会话窗口 提交数据

# db_session.add(user_obj) # insert into

# # 执行会话窗口中的所有操作

# db_session.commit() #rud

# db_session.close()

# .增加批量数据

# from create_table import User

# db_session.add_all([

#     User(name="AlexDSB"),

#     User(name="DragonFire"),

#     User(name="赵丽颖")

# ])

#

# db_session.commit()

# db_session.close()

#扩展：

# from create_table import User

# user1 = User(name="")

# user2 = User(name="")

# user3 = User(name="")

#

# db_session.add(user1)

# db_session.add(user2)

# db_session.add(user3)

#

# db_session.commit()

# db_session.close()

4.1外键增加数据

# 添加数据

from sqlalchemy.orm import sessionmaker

from create_table_ForeignKey import engine,Student,School

Session = sessionmaker(engine)

db_session = Session()

# .添加数据 - 笨

# sch_obj = School(name="OldBoyBeijing")

# db_session.add(sch_obj)

# db_session.commit()

#

# sch = db_session.query(School).filter(School.name == "OldBoyBeijing").first()

# stu_obj = Student(name="DragonFire",school_id=sch.id)

# db_session.add(stu_obj)

# db_session.commit()

# db_session.close()

# .添加数据 - 正向 relationship 版

# stu_obj = Student(name="小笼包",stu2sch=School(name="OldBoyShenzhen"))

# db_session.add(stu_obj)

# db_session.commit()

# db_session.close()

# .添加数据 - 反向 relationship 版

# sch_obj = School(name="OldBoyShanghai")

# sch_obj.sch2stu = [Student(name="赵丽颖"),Student(name="陈妍希")]

# db_session.add(sch_obj)

# db_session.commit()

# db_session.close()

五.删除数据

# 添加数据

from sqlalchemy.orm import sessionmaker

from create_table_ForeignKey import engine,Student,School

Session = sessionmaker(engine)

db_session = Session()

# .添加数据 - 笨

# sch_obj = School(name="OldBoyBeijing")

# db_session.add(sch_obj)

# db_session.commit()

#

# sch = db_session.query(School).filter(School.name == "OldBoyBeijing").first()

# stu_obj = Student(name="DragonFire",school_id=sch.id)

# db_session.add(stu_obj)

# db_session.commit()

# db_session.close()

# .添加数据 - 正向 relationship 版

# stu_obj = Student(name="小笼包",stu2sch=School(name="OldBoyShenzhen"))

# db_session.add(stu_obj)

# db_session.commit()

# db_session.close()

# .添加数据 - 反向 relationship 版

# sch_obj = School(name="OldBoyShanghai")

# sch_obj.sch2stu = [Student(name="赵丽颖"),Student(name="陈妍希")]

# db_session.add(sch_obj)

# db_session.commit()

# db_session.close()

5.1外键删除数据

# 添加数据

from sqlalchemy.orm import sessionmaker

from create_table_ForeignKey import engine,Student,School

Session = sessionmaker(engine)

db_session = Session()

# 删除数据

sch = db_session.query(School).filter(School.name=="OldBoyShanghai").first()

db_session.query(Student).filter(Student.school_id == sch.id).delete()

db_session.commit()

db_session.close()

六.查询数据

# 查询

# 会话窗口

from sqlalchemy.orm import sessionmaker

from create_table import engine

Session = sessionmaker(engine)

db_session = Session()

from create_table import User

# .简单查询

# select * from table

# user_list = db_session.query(User).all()

# for row in user_list:

#     print(row.id,row.name)

# user = db_session.query(User).first()

# print(user.id,user.name)

# .带条件的查询

# user_list = db_session.query(User).filter(User.id == ).all()

# print(user_list[].id,user_list[].name)

# user = db_session.query(User).filter_by(id=).first()

# print(user.id,user.name)

# user_list = db_session.query(User).filter(User.id >= ).all()

# for row in user_list:

#     print(row.name,row.id)

# 扩展 查看sql语句

# sql = db_session.query(User).filter(User.id >= )

# print(sql)

6.1外键查询

# 添加数据

from sqlalchemy.orm import sessionmaker

from create_table_ForeignKey import engine,Student,School

Session = sessionmaker(engine)

db_session = Session()

# .查询数据 - relationship 版 正向

# stu = db_session.query(Student).all()

# for row in stu:

#     print(row.id,row.name,row.school_id,row.stu2sch.name)

# .查询数据 - relationship 版 反向

# sch = db_session.query(School).all()

# for school in sch:

#     for student in school.sch2stu:

#         print(school.id,school.name,student.name)

6.2补充--查询

# 高级版查询操作,厉害了哦

# 老规矩

from create_table import User, engine

from sqlalchemy.orm import sessionmaker

Session = sessionmaker(engine)

db_session = Session()

# 查询数据表操作

# and or

# res = db_session.query(User).filter(User.id ==  or User.name == "DragonFire").all()

# print(res[].name,res)

#

# if False and True:

#     print("lihaile")

# from sqlalchemy.sql import and_ , or_

# ret = db_session.query(User).filter(and_(User.id == , User.name == 'DragonFire')).all()

# print(ret)

# ret = db_session.query(User).filter(or_(User.id == , User.name == 'DragonFire')).all()

# print(ret)

# ret = db_session.query(User).filter_by(id=,name="DragonFire").all()

# print(ret)

# 查询所有数据

# r1 = db_session.query(User).all()

# 查询数据 指定查询数据列 加入别名

# r2 = db_session.query(User.id.label("uid"),User.name.label("username")).first()

# print(r2.uid,r2.username) #  NBDragon

# 表达式筛选条件

# r3 = db_session.query(User).filter(User.name == "DragonFire").all()

# 原生SQL筛选条件

# r4 = db_session.query(User).filter_by(name='DragonFire').all()

# r5 = db_session.query(User).filter_by(name='DragonFire').first()

# 字符串匹配方式筛选条件 并使用 order_by进行排序

# from sqlalchemy.sql import text

# r6 = db_session.query(User).filter(text("id=:value and name=:name")).params(value=, name='DragonFire').first()

# print(r6.name)

# 原生SQL查询

# r7 = db_session.query(User).from_statement(text("SELECT * FROM User where name=:name")).params(name='DragonFire').all()

# 筛选查询列

# query的时候我们不在使用User ORM对象,而是使用User.name来对内容进行选取

# user_list = db_session.query(User.name).all()

# print(user_list)

# for row in user_list:

#     print(row.name)

# 别名映射  name as nick

# user_list = db_session.query(User.name.label("nick")).all()

# print(user_list)

# for row in user_list:

#     print(row.nick) # 这里要写别名了

# 筛选条件格式

# user_list = db_session.query(User).filter(User.name == "DragonFire").all()

# user_list = db_session.query(User).filter(User.name == "DragonFire").first()

# user_list = db_session.query(User).filter_by(name="DragonFire").first()

# for row in user_list:

#     print(row.nick)

# 复杂查询

# from sqlalchemy.sql import text

# user_list = db_session.query(User).filter(text("id<:value and name=:name")).params(value=,name="DragonFire")

# 查询语句

# from sqlalchemy.sql import text

# user_list = db_session.query(User).filter(text("select * from User id<:value and name=:name")).params(value=,name="DragonFire")

# 排序 :

# user_list = db_session.query(User).order_by(User.id.asc()).all()

# user_list = db_session.query(User).order_by(User.id.desc()).all()

# for row in user_list:

#     print(row.name,row.id)

# 其他查询条件

"""

ret = session.query(User).filter_by(name='DragonFire').all()

ret = session.query(User).filter(User.id > , User.name == 'DragonFire').all()

ret = session.query(User).filter(User.id.between(, ), User.name == 'DragonFire').all() # between 大于1小于3的

ret = session.query(User).filter(User.id.in_([,,])).all() # in_([,,]) 只查询id等于1,,4的

ret = session.query(User).filter(~User.id.in_([,,])).all() # ~xxxx.in_([,,]) 查询不等于1,,4的

ret = session.query(User).filter(User.id.in_(session.query(User.id).filter_by(name='DragonFire'))).all() 子查询

from sqlalchemy import and_, or_

ret = session.query(User).filter(and_(User.id > , User.name == 'DragonFire')).all()

ret = session.query(User).filter(or_(User.id < , User.name == 'DragonFire')).all()

ret = session.query(User).filter(

    or_(

        User.id < ,

        and_(User.name == 'eric', User.id > ),

        User.extra != ""

    )).all()

# select * from User where id< or (name="eric" and id>) or extra != "" 

# 通配符

ret = db_session.query(User).filter(User.name.like('e%')).all()

ret = db_session.query(User).filter(~User.name.like('e%')).all()

# 限制

ret = db_session.query(User)[:]

# 排序

ret = db_session.query(User).order_by(User.name.desc()).all()

ret = db_session.query(User).order_by(User.name.desc(), User.id.asc()).all()

# 分组

from sqlalchemy.sql import func

ret = db_session.query(User).group_by(User.extra).all()

ret = db_session.query(

    func.max(User.id),

    func.sum(User.id),

    func.min(User.id)).group_by(User.name).all()

ret = db_session.query(

    func.max(User.id),

    func.sum(User.id),

    func.min(User.id)).group_by(User.name).having(func.min(User.id) >).all()

"""

# ret = db_session.query(User).filter(User.id.between(, )).all() # between 大于1小于3的

# print(ret)

# ret = db_session.query(User).filter(User.id.in_([,])).all() # in_([,,]) 只查询id等于1,,4的

# ret = db_session.query(User).filter(~User.id.in_([,,])).all() # ~xxxx.in_([,,]) 查询不等于1,,4的

# print(ret)

# from sqlalchemy.sql import and_, or_

#

# ret = db_session.query(User).filter(

#     or_(

#         User.id < ,

#         and_(User.name == 'eric', User.id > ),

#         User.name != ""

#     ))

# print(ret)

# 关闭连接

db_session.close()

七更新数据

# 更新修改数据

from sqlalchemy.orm import sessionmaker

from create_table import engine, User

Session = sessionmaker(engine)

db_session = Session()

# .修改数据 - 先查询预修改的数据

# update `user` set `name` = "" where id =

# res = db_session.query(User).filter(User.name=="Ywb").update({"name":"武配齐"})

# print(res)

# db_session.commit()

# db_session.close()

# res = db_session.query(User).filter(User.id >= ).update({"name":})

# print(res)

# db_session.commit()

# db_session.close()

7.1外键更新数据

# 添加数据

from sqlalchemy.orm import sessionmaker

from create_table_ForeignKey import engine,Student,School

Session = sessionmaker(engine)

db_session = Session()

# 修改数据

sch = db_session.query(School).filter(School.name=="OldBoyShanghai").first()

db_session.query(Student).filter(Student.name == "小笼包").update({"school_id":sch.id})

db_session.commit()

db_session.close()

7.2补充更新

#高级版更新操作

from create_table import User,engine

from sqlalchemy.orm import sessionmaker

Session = sessionmaker(engine)

db_session = Session()

#直接修改

# db_session.query(User).filter(User.id > ).update({"name" : ""})

#在原有值基础上添加 -

db_session.query(User).filter(User.id > ).update({User.name: User.name + ""}, synchronize_session=False)

db_session.commit()

#在原有值基础上添加 -

# db_session.query(User).filter(User.id > ).update({"age": User.age + }, synchronize_session="evaluate")

# db_session.commit()

八.多对多的表结构建立

from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

from sqlalchemy import Column,Integer,String,ForeignKey

from sqlalchemy.orm import relationship

class Girls(Base):

    __tablename__ = "girl"

    id = Column(Integer(),primary_key=True,autoincrement=True)

    name = Column(String())

    girl2boy = relationship("Boy",secondary="Hote",backref="boy2girl")

class Boy(Base):

    __tablename__ ="boy"

    id = Column(Integer(),primary_key=True,autoincrement=True)

    name = Column(String())

class Hote(Base):

    __tablename__ ="hote"

    id = Column(Integer(),primary_key=True,autoincrement=True)

    name = Column(String())

    girl_id = Column(Integer, ForeignKey("girl.id"))

    boy_id = Column(Integer, ForeignKey("boy.id"))

from sqlalchemy import create_engine

engine = create_engine("mysql+pymysql://root:@127.0.0.1:3306/day127?charset=utf8")

Base.metadata.create_all(engine)

8.1多对多的增加数据

from sqlalchemy.orm import sessionmaker

from app.M2m import engine

Session = sessionmaker(engine)

db_session = Session()

#.增加

 # .通过Boy添加Girl和Hotel数据

boy = Boy(name="DragonFire")

boy.girl2boy = [Girls(name="赵丽颖"),Girls(name="Angelababy")]

db_session.add(boy)

db_session.commit()

 # .通过Girl添加Boy和Hotel数据

girl = Girls(name="珊珊")

girl.boys = [Boy(name="Dragon")]

db_session.add(girl)

db_session.commit()

8.2多对多的查询数据

  from my_M2M import Girl,Boy,Hotel,engine

  # 创建连接

  from sqlalchemy.orm import sessionmaker

  # 创建数据表操作对象 sessionmaker

  DB_session = sessionmaker(engine)

  db_session = DB_session()

  # .通过Boy查询约会过的所有Girl

 hotel = db_session.query(Boy).all()

 for row in hotel:

     for row2 in row.girl2boy:

         print(row.name,row2.name)

 # .通过Girl查询约会过的所有Boy

 hotel = db_session.query(Girl).all()

 for row in hotel:

     for row2 in row.boys:

         print(row.name,row2.name)

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