import sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column,Integer,String,Float,Enum,Date
from sqlalchemy.orm import sessionmaker

Base=declarative_base()

class Student(Base):
    __tablename__='Stu'
    id=Column(Integer,primary_key=True,nullable=False,autoincrement=True)
    name=Column(String(64),nullable=False)
    age=Column(Float,unique=True)

    def __repr__(self):
        return '<{} (id:{}, name:{}, age:{})>'.format(self.__class__.__name__,self.id,self.name,self.age)

    __str__=__repr__


engine=sqlalchemy.create_engine("mysql+pymysql://root:cruces@localhost:3306/uranus",echo=True)

# create table,drop table
# Base.metadata.create_all(engine)
# Base.metadata.drop_all(engine)

Session=sessionmaker()
session=Session(bind=engine)

try:
    # t1=Student()
    # t1.name='ppp'
    # t1.age=44
    # t2=Student()
    # t2.name='ooo'
    # t2.age=88
    lst=[]
    for b in range(5):
        t=Student()
        t.name='uiop'+str(b)
        t.age=30+b
        lst.append(t)

    session.add_all(lst)
    session.commit()
except Exception as e:
    print(e.args,e.__dict__,e)
    session.rollback()
finally:
    pass

try:
    s1=Student()
    s1.name='pp'
    s1.age=33
    session.add(s1)
    print(s1.id)
    session.commit()
    print(s1.id,999999999999999999999)

    s1.age=88
    # session.add(s1)  # not necessary
    session.commit()

except Exception as e:
    print(e.args,e.__dict__,e)
    session.rollback()
finally:
    pass

查詢

try:
    queryobj=session.query(Student).filter(Student.name=='pp')
    for b in queryobj:
        print(b)
except Exception as e:
    print(e.__cause__)
finally:
    pass

get方法用主鍵查詢,返回一條傳入類的例項

try:
    s=session.query(Student).get(2)
    print(s)
    s.name='uiop'
    s.age=999
    print(s)
    session.commit()
    
except Exception as e:
    print(e.__traceback__)
finally:
    pass

刪除

try:
    s=Student()
    s.id=2
    session.delete(s)
    session.commit()
except Exception as e:
    print(e.__cause__,e.__class__,e)
    session.rollback()
finally:
    pass

try:
    # s=session.query(Student).filter(Student.id==2)
    s=session.query(Student).get(2)
    session.delete(s)
    session.commit()
except Exception as e:
    print(e.__cause__)
finally:
    pass