标签:closed image root type 实现 mysql 信息 target port
SQLAlchemy是Python编程语言下的一款ORM框架,该框架建立在数据库API之上,使用关系对象映射进行数据库操作,简言之便是:将对象转换成SQL,然后使用数据API执行SQL并获取执行结果。
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...]
更多详见:http:
/
/
docs.sqlalchemy.org
/
en
/
latest
/
dialects
/
index.html
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 4 from sqlalchemy import create_engine 5 6 7 engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5) 8 9 engine.execute( 10 "INSERT INTO ts_test (a, b) VALUES (‘2‘, ‘v1‘)" 11 ) 12 13 engine.execute( 14 "INSERT INTO ts_test (a, b) VALUES (%s, %s)", 15 ((555, "v1"),(666, "v1"),) 16 ) 17 engine.execute( 18 "INSERT INTO ts_test (a, b) VALUES (%(id)s, %(name)s)", 19 id=999, name="v1" 20 ) 21 22 result = engine.execute(‘select * from ts_test‘) 23 result.fetchall()
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 4 from sqlalchemy import create_engine 5 6 7 engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5) 8 9 10 # 事务操作 11 with engine.begin() as conn: 12 conn.execute("insert into table (x, y, z) values (1, 2, 3)") 13 conn.execute("my_special_procedure(5)") 14 15 16 conn = engine.connect() 17 # 事务操作 18 with conn.begin(): 19 conn.execute("some statement", {‘x‘:5, ‘y‘:10})
1 ‘‘‘ 2 使用 Schema Type/SQL Expression Language/Engine/ConnectionPooling/Dialect 进行数据库操作。Engine使用Schema Type创建一个特定的结构对象,之后通过SQL Expression Language将该对象转换成SQL语句,然后通过 ConnectionPooling 连接数据库,再然后通过 Dialect 执行SQL,并获取结果。 3 ‘‘‘ 4 5 6 #!/usr/bin/env python 7 # -*- coding:utf-8 -*- 8 9 from sqlalchemy import create_engine, Table, Column, Integer, String, MetaData, ForeignKey 10 11 metadata = MetaData() 12 13 user = Table(‘user‘, metadata, 14 Column(‘id‘, Integer, primary_key=True), 15 Column(‘name‘, String(20)), 16 ) 17 18 color = Table(‘color‘, metadata, 19 Column(‘id‘, Integer, primary_key=True), 20 Column(‘name‘, String(20)), 21 ) 22 engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5) 23 24 metadata.create_all(engine) 25 # metadata.clear() 26 # metadata.remove()
#!/usr/bin/env python # -*- coding:utf-8 -*- from sqlalchemy import create_engine, Table, Column, Integer, String, MetaData, ForeignKey metadata = MetaData() user = Table(‘user‘, metadata, Column(‘id‘, Integer, primary_key=True), Column(‘name‘, String(20)), ) color = Table(‘color‘, metadata, Column(‘id‘, Integer, primary_key=True), Column(‘name‘, String(20)), ) engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5) conn = engine.connect() # 创建SQL语句,INSERT INTO "user" (id, name) VALUES (:id, :name) conn.execute(user.insert(),{‘id‘:7,‘name‘:‘seven‘}) conn.close() # sql = user.insert().values(id=123, name=‘wu‘) # conn.execute(sql) # conn.close() # sql = user.delete().where(user.c.id > 1) # sql = user.update().values(fullname=user.c.name) # sql = user.update().where(user.c.name == ‘jack‘).values(name=‘ed‘) # sql = select([user, ]) # sql = select([user.c.id, ]) # sql = select([user.c.name, color.c.name]).where(user.c.id==color.c.id) # sql = select([user.c.name]).order_by(user.c.name) # sql = select([user]).group_by(user.c.name) # result = conn.execute(sql) # print result.fetchall() # conn.close() 更多内容详见: http://www.jianshu.com/p/e6bba189fcbd http://docs.sqlalchemy.org/en/latest/core/expression_api.html
注:SQLAlchemy无法修改表结构,如果需要可以使用SQLAlchemy开发者开源的另外一个软件Alembic来完成。
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 4 from sqlalchemy.ext.declarative import declarative_base 5 from sqlalchemy import Column, Integer, String 6 from sqlalchemy.orm import sessionmaker 7 from sqlalchemy import create_engine 8 9 engine = create_engine("mysql+mysqldb://root:123@127.0.0.1:3306/s11", max_overflow=5) 10 11 Base = declarative_base() 12 13 14 class User(Base): 15 __tablename__ = ‘users‘ 16 id = Column(Integer, primary_key=True) 17 name = Column(String(50)) 18 19 # 寻找Base的所有子类,按照子类的结构在数据库中生成对应的数据表信息 20 # Base.metadata.create_all(engine) 21 22 Session = sessionmaker(bind=engine) 23 session = Session() 24 25 26 # ########## 增 ########## 27 # u = User(id=2, name=‘sb‘) 28 # session.add(u) 29 # session.add_all([ 30 # User(id=3, name=‘sb‘), 31 # User(id=4, name=‘sb‘) 32 # ]) 33 # session.commit() 34 35 # ########## 删除 ########## 36 # session.query(User).filter(User.id > 2).delete() 37 # session.commit() 38 39 # ########## 修改 ########## 40 # session.query(User).filter(User.id > 2).update({‘cluster_id‘ : 0}) 41 # session.commit() 42 # ########## 查 ########## 43 # ret = session.query(User).filter_by(name=‘sb‘).first() 44 45 # ret = session.query(User).filter_by(name=‘sb‘).all() 46 # print ret 47 48 # ret = session.query(User).filter(User.name.in_([‘sb‘,‘bb‘])).all() 49 # print ret 50 51 # ret = session.query(User.name.label(‘name_label‘)).all() 52 # print ret,type(ret) 53 54 # ret = session.query(User).order_by(User.id).all() 55 # print ret 56 57 # ret = session.query(User).order_by(User.id)[1:3] 58 # print ret 59 # session.commit()
标签:closed image root type 实现 mysql 信息 target port
原文地址:https://www.cnblogs.com/JcrLive/p/12488614.html