博客转载于 http://www.cnblogs.com/haiyan123/p/8270520.html

一. 介绍

SQLAlchemy是一个基于Python实现的ORM框架。该框架建立在 DB API之上，使用关系对象映射进行数据库操作，简言之便是：将类和对象转换成SQL，然后使用数据API执行SQL并获取执行结果。

 pip install sqlalchemy -i http://pypi.douban.com/simple  --trusted-host pypi.douban.com 

组成部分：

  • Engine，框架的引擎
  • Connection Pooling ，数据库连接池
  • Dialect，选择连接数据库的DB API种类
  • Schema/Types，架构和类型
  • SQL Exprression Language，SQL表达式语言

SQLAlchemy本身无法操作数据库，其必须以来pymsql等第三方插件，Dialect用于和数据API进行交流，根据配置文件的不同调用不同的数据库API，从而实现对数据库的操作，如：

MySQL-Python

    mysql+mysqldb://<user>:<password>@<host>[:<port>]/<dbname>

pymysql

    mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]

MySQL-Connector

    mysql+mysqlconnector://<user>:<password>@<host>[:<port>]/<dbname>

cx_Oracle

    oracle+cx_oracle://user:pass@host:port/dbname[?key=value&key=value...]

更多：http://docs.sqlalchemy.org/en/latest/dialects/index.html

二. 使用

1. 执行原生SQL语句

import time

import threading

import sqlalchemy

from sqlalchemy import create_engine

from sqlalchemy.engine.base import Engine

engine = create_engine(

    "mysql+pymysql://root:123@127.0.0.1:3306/t1?charset=utf8",

    max_overflow=0,  # 超过连接池大小外最多创建的连接

    pool_size=5,  # 连接池大小

    pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错

    pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）

)

def task(arg):

    conn = engine.raw_connection()

    cursor = conn.cursor()

    cursor.execute(

        "select * from t1"

    )

    result = cursor.fetchall()

    cursor.close()

    conn.close()

for i in range(20):

    t = threading.Thread(target=task, args=(i,))

    t.start()
 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5 import sqlalchemy

 6 from sqlalchemy import create_engine

 7 from sqlalchemy.engine.base import Engine

 8

 9 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/t1", max_overflow=0, pool_size=5)

10

11

12 def task(arg):

13     conn = engine.contextual_connect()

14     with conn:

15         cur = conn.execute(

16             "select * from t1"

17         )

18         result = cur.fetchall()

19         print(result)

20

21

22 for i in range(20):

23     t = threading.Thread(target=task, args=(i,))

24     t.start()
 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5 import sqlalchemy

 6 from sqlalchemy import create_engine

 7 from sqlalchemy.engine.base import Engine

 8 from sqlalchemy.engine.result import ResultProxy

 9 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/t1", max_overflow=0, pool_size=5)

10

11

12 def task(arg):

13     cur = engine.execute("select * from t1")

14     result = cur.fetchall()

15     cur.close()

16     print(result)

17

18

19 for i in range(20):

20     t = threading.Thread(target=task, args=(i,))

21     t.start()

注意: 查看连接 show status like 'Threads%';

2. ORM

a. 创建数据库表

 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import datetime

 4 from sqlalchemy import create_engine

 5 from sqlalchemy.ext.declarative import declarative_base

 6 from sqlalchemy import Column, Integer, String, Text, ForeignKey, DateTime, UniqueConstraint, Index

 7

 8 Base = declarative_base()

 9

10

11 class Users(Base):

12     __tablename__ = 'users'

13

14     id = Column(Integer, primary_key=True)

15     name = Column(String(32), index=True, nullable=False)

16     # email = Column(String(32), unique=True)

17     # ctime = Column(DateTime, default=datetime.datetime.now)

18     # extra = Column(Text, nullable=True)

19

20     __table_args__ = (

21         # UniqueConstraint('id', 'name', name='uix_id_name'),

22         # Index('ix_id_name', 'name', 'email'),

23     )

24

25

26 def init_db():

27     """

28     根据类创建数据库表

29     :return:

30     """

31     engine = create_engine(

32         "mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8",

33         max_overflow=0,  # 超过连接池大小外最多创建的连接

34         pool_size=5,  # 连接池大小

35         pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错

36         pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）

37     )

38

39     Base.metadata.create_all(engine)

40

41

42 def drop_db():

43     """

44     根据类删除数据库表

45     :return:

46     """

47     engine = create_engine(

48         "mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8",

49         max_overflow=0,  # 超过连接池大小外最多创建的连接

50         pool_size=5,  # 连接池大小

51         pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错

52         pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）

53     )

54

55     Base.metadata.drop_all(engine)

56

57

58 if __name__ == '__main__':

59     drop_db()

60     init_db()
  1 #!/usr/bin/env python

  2 # -*- coding:utf-8 -*-

  3 import datetime

  4 from sqlalchemy import create_engine

  5 from sqlalchemy.ext.declarative import declarative_base

  6 from sqlalchemy import Column, Integer, String, Text, ForeignKey, DateTime, UniqueConstraint, Index

  7 from sqlalchemy.orm import relationship

  8

  9 Base = declarative_base()

 10

 11

 12 # ##################### 单表示例 #########################

 13 class Users(Base):

 14     __tablename__ = 'users'

 15

 16     id = Column(Integer, primary_key=True)

 17     name = Column(String(32), index=True)

 18     age = Column(Integer, default=18)

 19     email = Column(String(32), unique=True)

 20     ctime = Column(DateTime, default=datetime.datetime.now)

 21     extra = Column(Text, nullable=True)

 22

 23     __table_args__ = (

 24         # UniqueConstraint('id', 'name', name='uix_id_name'),

 25         # Index('ix_id_name', 'name', 'extra'),

 26     )

 27

 28

 29 class Hosts(Base):

 30     __tablename__ = 'hosts'

 31

 32     id = Column(Integer, primary_key=True)

 33     name = Column(String(32), index=True)

 34     ctime = Column(DateTime, default=datetime.datetime.now)

 35

 36

 37 # ##################### 一对多示例 #########################

 38 class Hobby(Base):

 39     __tablename__ = 'hobby'

 40     id = Column(Integer, primary_key=True)

 41     caption = Column(String(50), default='篮球')

 42

 43

 44 class Person(Base):

 45     __tablename__ = 'person'

 46     nid = Column(Integer, primary_key=True)

 47     name = Column(String(32), index=True, nullable=True)

 48     hobby_id = Column(Integer, ForeignKey("hobby.id"))

 49

 50     # 与生成表结构无关，仅用于查询方便

 51     hobby = relationship("Hobby", backref='pers')

 52

 53

 54 # ##################### 多对多示例 #########################

 55

 56 class Server2Group(Base):

 57     __tablename__ = 'server2group'

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

 59     server_id = Column(Integer, ForeignKey('server.id'))

 60     group_id = Column(Integer, ForeignKey('group.id'))

 61

 62

 63 class Group(Base):

 64     __tablename__ = 'group'

 65     id = Column(Integer, primary_key=True)

 66     name = Column(String(64), unique=True, nullable=False)

 67

 68     # 与生成表结构无关，仅用于查询方便

 69     servers = relationship('Server', secondary='server2group', backref='groups')

 70

 71

 72 class Server(Base):

 73     __tablename__ = 'server'

 74

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

 76     hostname = Column(String(64), unique=True, nullable=False)

 77

 78

 79 def init_db():

 80     """

 81     根据类创建数据库表

 82     :return:

 83     """

 84     engine = create_engine(

 85         "mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8",

 86         max_overflow=0,  # 超过连接池大小外最多创建的连接

 87         pool_size=5,  # 连接池大小

 88         pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错

 89         pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）

 90     )

 91

 92     Base.metadata.create_all(engine)

 93

 94

 95 def drop_db():

 96     """

 97     根据类删除数据库表

 98     :return:

 99     """

100     engine = create_engine(

101         "mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8",

102         max_overflow=0,  # 超过连接池大小外最多创建的连接

103         pool_size=5,  # 连接池大小

104         pool_timeout=30,  # 池中没有线程最多等待的时间，否则报错

105         pool_recycle=-1  # 多久之后对线程池中的线程进行一次连接的回收（重置）

106     )

107

108     Base.metadata.drop_all(engine)

109

110

111 if __name__ == '__main__':

112     drop_db()

113     init_db()

b. 操作数据库表

#!/usr/bin/env python

# -*- coding:utf-8 -*-

from sqlalchemy.orm import sessionmaker

from sqlalchemy import create_engine

from models import Users

engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)
##############方式一########################

Session = sessionmaker(bind=engine)

# 每次执行数据库操作时，都需要创建一个session

session = Session()

# ############# 执行ORM操作 #############

obj1 = Users(name="alex1")

session.add(obj1)

# 提交事务

session.commit()

# 关闭session

session.close()

######################方式二####################

# 方式二：支持线程安全，为每个线程创建一个session
# - threading.Local
# - 唯一标识
# ScopedSession对象
# self.registry(), 加括号 创建session
# self.registry(), 加括号 创建session
# self.registry(), 加括号 创建session
from greenlet import getcurrent as get_ident

Session = sessionmaker(bind=engine)

session = scoped_session(Session,get_ident)
# session.add
# 操作
session.remove()













 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from db import Users

11

12 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)

13 Session = sessionmaker(bind=engine)

14

15

16 def task(arg):

17     session = Session()

18

19     obj1 = Users(name="alex1")

20     session.add(obj1)

21

22     session.commit()

23

24

25 for i in range(10):

26     t = threading.Thread(target=task, args=(i,))

27     t.start()














 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from sqlalchemy.sql import text

11

12 from db import Users, Hosts

13

14 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)

15 Session = sessionmaker(bind=engine)

16

17 session = Session()

18

19 # ################ 添加 ################

20 """

21 obj1 = Users(name="wupeiqi")

22 session.add(obj1)

23

24 session.add_all([

25     Users(name="wupeiqi"),

26     Users(name="alex"),

27     Hosts(name="c1.com"),

28 ])

29 session.commit()

30 """

31

32 # ################ 删除 ################

33 """

34 session.query(Users).filter(Users.id > 2).delete()

35 session.commit()

36 """

37 # ################ 修改 ################

38 """

39 session.query(Users).filter(Users.id > 0).update({"name" : "099"})

40 session.query(Users).filter(Users.id > 0).update({Users.name: Users.name + "099"}, synchronize_session=False)

41 session.query(Users).filter(Users.id > 0).update({"age": Users.age + 1}, synchronize_session="evaluate")

42 session.commit()

43 """

44 # ################ 查询 ################

45 """

46 r1 = session.query(Users).all()

47 r2 = session.query(Users.name.label('xx'), Users.age).all()

48 r3 = session.query(Users).filter(Users.name == "alex").all()

49 r4 = session.query(Users).filter_by(name='alex').all()

50 r5 = session.query(Users).filter_by(name='alex').first()

51 r6 = session.query(Users).filter(text("id<:value and name=:name")).params(value=224, name='fred').order_by(Users.id).all()

52 r7 = session.query(Users).from_statement(text("SELECT * FROM users where name=:name")).params(name='ed').all()

53 """

54

55

56 session.close()














 1 #　条件

 2 ret = session.query(Users).filter_by(name='alex').all()

 3 ret = session.query(Users).filter(Users.id > 1, Users.name == 'eric').all()

 4 ret = session.query(Users).filter(Users.id.between(1, 3), Users.name == 'eric').all()

 5 ret = session.query(Users).filter(Users.id.in_([1,3,4])).all()

 6 ret = session.query(Users).filter(~Users.id.in_([1,3,4])).all()

 7 ret = session.query(Users).filter(Users.id.in_(session.query(Users.id).filter_by(name='eric'))).all()

 8 from sqlalchemy import and_, or_

 9 ret = session.query(Users).filter(and_(Users.id > 3, Users.name == 'eric')).all()

10 ret = session.query(Users).filter(or_(Users.id < 2, Users.name == 'eric')).all()

11 ret = session.query(Users).filter(

12     or_(

13         Users.id < 2,

14         and_(Users.name == 'eric', Users.id > 3),

15         Users.extra != ""

16     )).all()

17

18

19 # 通配符

20 ret = session.query(Users).filter(Users.name.like('e%')).all()

21 ret = session.query(Users).filter(~Users.name.like('e%')).all()

22

23 # 限制

24 ret = session.query(Users)[1:2]

25

26 # 排序

27 ret = session.query(Users).order_by(Users.name.desc()).all()

28 ret = session.query(Users).order_by(Users.name.desc(), Users.id.asc()).all()

29

30 # 分组

31 from sqlalchemy.sql import func

32

33 ret = session.query(Users).group_by(Users.extra).all()

34 ret = session.query(

35     func.max(Users.id),

36     func.sum(Users.id),

37     func.min(Users.id)).group_by(Users.name).all()

38

39 ret = session.query(

40     func.max(Users.id),

41     func.sum(Users.id),

42     func.min(Users.id)).group_by(Users.name).having(func.min(Users.id) >2).all()

43

44 # 连表

45

46 ret = session.query(Users, Favor).filter(Users.id == Favor.nid).all()

47

48 ret = session.query(Person).join(Favor).all()

49

50 ret = session.query(Person).join(Favor, isouter=True).all()

51

52

53 # 组合

54 q1 = session.query(Users.name).filter(Users.id > 2)

55 q2 = session.query(Favor.caption).filter(Favor.nid < 2)

56 ret = q1.union(q2).all()

57

58 q1 = session.query(Users.name).filter(Users.id > 2)

59 q2 = session.query(Favor.caption).filter(Favor.nid < 2)

60 ret = q1.union_all(q2).all()














 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from sqlalchemy.sql import text

11 from sqlalchemy.engine.result import ResultProxy

12 from db import Users, Hosts

13

14 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)

15 Session = sessionmaker(bind=engine)

16

17 session = Session()

18

19 # 查询

20 # cursor = session.execute('select * from users')

21 # result = cursor.fetchall()

22

23 # 添加

24 cursor = session.execute('insert into users(name) values(:value)',params={"value":'wupeiqi'})

25 session.commit()

26 print(cursor.lastrowid)

27

28 session.close()














 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from sqlalchemy.sql import text

11 from sqlalchemy.engine.result import ResultProxy

12 from db import Users, Hosts, Hobby, Person

13

14 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)

15 Session = sessionmaker(bind=engine)

16 session = Session()

17 # 添加

18 """

19 session.add_all([

20     Hobby(caption='乒乓球'),

21     Hobby(caption='羽毛球'),

22     Person(name='张三', hobby_id=3),

23     Person(name='李四', hobby_id=4),

24 ])

25

26 person = Person(name='张九', hobby=Hobby(caption='姑娘'))

27 session.add(person)

28

29 hb = Hobby(caption='人妖')

30 hb.pers = [Person(name='文飞'), Person(name='博雅')]

31 session.add(hb)

32

33 session.commit()

34 """

35

36 # 使用relationship正向查询

37 """

38 v = session.query(Person).first()

39 print(v.name)

40 print(v.hobby.caption)

41 """

42

43 # 使用relationship反向查询

44 """

45 v = session.query(Hobby).first()

46 print(v.caption)

47 print(v.pers)

48 """

49

50 session.close()














 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from sqlalchemy.sql import text

11 from sqlalchemy.engine.result import ResultProxy

12 from db import Users, Hosts, Hobby, Person, Group, Server, Server2Group

13

14 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)

15 Session = sessionmaker(bind=engine)

16 session = Session()

17 # 添加

18 """

19 session.add_all([

20     Server(hostname='c1.com'),

21     Server(hostname='c2.com'),

22     Group(name='A组'),

23     Group(name='B组'),

24 ])

25 session.commit()

26

27 s2g = Server2Group(server_id=1, group_id=1)

28 session.add(s2g)

29 session.commit()

30

31

32 gp = Group(name='C组')

33 gp.servers = [Server(hostname='c3.com'),Server(hostname='c4.com')]

34 session.add(gp)

35 session.commit()

36

37

38 ser = Server(hostname='c6.com')

39 ser.groups = [Group(name='F组'),Group(name='G组')]

40 session.add(ser)

41 session.commit()

42 """

43

44

45 # 使用relationship正向查询

46 """

47 v = session.query(Group).first()

48 print(v.name)

49 print(v.servers)

50 """

51

52 # 使用relationship反向查询

53 """

54 v = session.query(Server).first()

55 print(v.hostname)

56 print(v.groups)

57 """

58

59

60 session.close()














 1 #!/usr/bin/env python

 2 # -*- coding:utf-8 -*-

 3 import time

 4 import threading

 5

 6 from sqlalchemy.ext.declarative import declarative_base

 7 from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

 8 from sqlalchemy.orm import sessionmaker, relationship

 9 from sqlalchemy import create_engine

10 from sqlalchemy.sql import text, func

11 from sqlalchemy.engine.result import ResultProxy

12 from db import Users, Hosts, Hobby, Person, Group, Server, Server2Group

13

14 engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6?charset=utf8", max_overflow=0, pool_size=5)

15 Session = sessionmaker(bind=engine)

16 session = Session()

17

18 # 关联子查询

19 subqry = session.query(func.count(Server.id).label("sid")).filter(Server.id == Group.id).correlate(Group).as_scalar()

20 result = session.query(Group.name, subqry)

21 """

22 SELECT `group`.name AS group_name, (SELECT count(server.id) AS sid

23 FROM server

24 WHERE server.id = `group`.id) AS anon_1

25 FROM `group`

26 """

27

28

29 # 原生SQL

30 """

31 # 查询

32 cursor = session.execute('select * from users')

33 result = cursor.fetchall()

34

35 # 添加

36 cursor = session.execute('insert into users(name) values(:value)',params={"value":'wupeiqi'})

37 session.commit()

38 print(cursor.lastrowid)

39 """

40

41 session.close()








基本增删改查补充






#!/usr/bin/env python

# -*- coding:utf-8 -*-

import time

import threading

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy import Column, Integer, String, ForeignKey, UniqueConstraint, Index

from sqlalchemy.orm import sessionmaker, relationship

from sqlalchemy import create_engine

from sqlalchemy.sql import text

from db import Users, Hosts

engine = create_engine("mysql+pymysql://root:123@127.0.0.1:3306/s6", max_overflow=0, pool_size=5)

Session = sessionmaker(bind=engine)

session = Session()

# ################ 添加 ################

"""

obj1 = Users(name="wupeiqi")

session.add(obj1)

#批量添加

session.add_all([

    Users(name="wupeiqi"),

    Users(name="alex"),

    Hosts(name="c1.com"),

])

session.commit()

"""

# ################ 删除 ################

"""

session.query(Users).filter(Users.id > 2).delete()

session.commit()

"""

# ################ 修改 ################

"""

session.query(Users).filter(Users.id > 0).update({"name" : "099"})

session.query(Users).filter(Users.id > 0).update({Users.name: Users.name + "099"}, synchronize_session=False) #字符串

session.query(Users).filter(Users.id > 0).update({"age": Users.age + 1}, synchronize_session="evaluate")  #数字

session.commit()

"""

# ################ 查询 ################

"""

r1 = session.query(Users).all()

r2 = session.query(Users.name.label('xx'), Users.age).all()   #lable #as xx

r3 = session.query(Users).filter(Users.name == "alex").all()

r4 = session.query(Users).filter_by(name='alex').all()   #如果里面写条件就用filter_by,和上面filter查询是一回事，只是一种不同的方式

r5 = session.query(Users).filter_by(name='alex').first()

r6 = session.query(Users).filter(text("id<:value and name=:name")).params(value=224, name='fred').order_by(Users.id).all()  #查询里面如果有动态传参的时候，吧它包在text里面，:value,:name这样的语法后面用.params来进行格式化

r7 = session.query(Users).from_statement(text("SELECT * FROM users where name=:name")).params(name='ed').all()  #上面的这个方式也可以用这一种 ，直接可以进行SQL语句的查询

"""

session.close()



												


											
SqlAlchemy操作（一）的更多相关文章
	

    
						
  1. flask 操作mysql的两种方式-sqlalchemy操作
		
    flask 操作mysql的两种方式-sqlalchemy操作 二.ORM sqlalchemy操作 #coding=utf-8 # model.py from app import db class ...
    
		
    2. 
						
  2. Python3.x：SQLAlchemy操作数据库
		
    Python3.x:SQLAlchemy操作数据库 前言 SQLAlchemy是一个ORM框架(Object Rational Mapping,对象关系映射),它可以帮助我们更加优雅.更加高效的实现数 ...
    
		
    3. 
						
  3. Python之Mysql及SQLAlchemy操作总结
		
    一.Mysql命令总结 1.创建库 create database test1; 2.授权一个用户 grant all privileges on *.* to 'feng'@'%' identifi ...
    
		
    4. 
						
  4. sqlalchemy操作
		
    Sqlalchemy ORM操作归类 #简单查询 #注意User是一个类对象,user_table是数据库中的表 #session = sessionmaker() #创建了一个自己定义了的 Sess ...
    
		
    5. 
						
  5. Python 使用sqlalchemy操作MYSQL
		
    1. 安装sqlalchemy库 SQL操作引擎可能需要pymysql,故要安装如下两个程序 pip install sqlalchemy pip instal pymysql
    
		
    6. 
						
  6. 04：sqlalchemy操作数据库
		
    目录: 1.1 ORM介绍(作用:不用原生SQL语句对数据库操作) 1.2 安装sqlalchemy并创建表 1.3 使用sqlalchemy对表基本操作 1.4 一对多外键关联 1.5 sqlalc ...
    
		
    7. 
						
  7. SqlAlchemy操作（三）
		
    1.基于SQLALCHEMY建表 from sqlalchemy.ext.declarative import declarative_base from sqlalchemy import Colu ...
    
		
    8. 
								
  8. SqlAlchemy操作（二）
		
    SQLALchemy初始化链接数据库 1. 数据库配置. https://www.cnblogs.com/mengbin0546/p/10124560.html 2.  python端操作. 一.   ...
    
		
    9. 
						
  9. python  ORM - sqlalchemy 操作使用
		
    python操作数据库 使用 ORM - sqlalchemy,pymsql 安装: pip install pymsq pip install sqlalchemy 一. '''连接数据库'''   ...
    
		
    10. 
		

	


随机推荐
	

    
									
  1. Ubuntu --- not enough free disk space
			
    Ubuntu系统更新时出现not enough free disk space. 原因是系统的就内核占满了/boot 的空间,只要将旧内核删除就ok了 首先,命令 uname -r  查看当前内核,( ...
    
			
    2. 
						
  2. 15-js提交表单的简单检测实例
			
    <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding= ...
    
			
    3. 
						
  3. centos7下编译安装php-7.0.15(PHP-FPM)
			
    centos7下编译安装php-7.0.15(PHP-FPM) 一.下载php7源码包 http://php.net/downloads.php 如:php-7.0.15.tar.gz 二.安装所需依 ...
    
			
    4. 
						
  4. css布局---各种居中
			
    居中是我们使用css来布局时常遇到的情况.使用css来进行居中时,有时一个属性就能搞定,有时则需要一定的技巧才能兼容到所有浏览器,本文就居中的一些常用方法做个简单的介绍. 注:本文所讲方法除了特别说明 ...
    
			
    5. 
						
  5. PAT 1079 延迟的回文数（代码+思路）
			
    1079 延迟的回文数(20 分) 给定一个 k+1 位的正整数 N,写成 a​k​​⋯a​1​​a​0​​ 的形式,其中对所有 i 有 0≤a​i​​<10 且 a​k​​>0.N 被称 ...
    
			
    6. 
						
  6. 80% UI 初学者走过的弯路，你走了几条？
			
    关于UI 对于初学UI设计的人而言,可能对UI具体是做什么,或者自己是否能顺利转行胜任这样的岗位存在一定的顾虑,今天我们就来重点说说UI是做什么的,以及学UI到有哪些需要避免的弯路. 1.UI设计是做 ...
    
			
    7. 
						
  7. glog日志
			
    google 开源日志库 #include <glog/logging.h> yum install glog
    
			
    8. 
						
  8. part1:4-linux快速体验
			
    1.Linux部分目录结构介绍 /:根目录,一般根目录下只存放目录,尽量不要存放文件:/etc./bin./dev./lib./sbin应该和根目录放置在一个分区中. /bin:可执行二进制文件目录, ...
    
			
    9. 
						
  9. python函数、装饰器、迭代器、生成器
			
    目录: 函数补充进阶 函数对象 函数的嵌套 名称空间与作用域 闭包函数 函数之装饰器 函数之迭代器 函数之生成器 内置函数 一.函数补充进阶 1.函数对象:  函数是第一类对象,即函数可以当作数据传递 ...
    
			
    10. 
						
  10. servlet-servletContext网站计数器
			
    1.在项目中新建文件夹新建文件nums.txt 2.在web.xml文件配置 <servlet>     <description>This is the descriptio ...
    
			
    11.