本文整理自网络,侵删。
SQLAlchemy的理念是,SQL数据库的量级和性能重要于对象集合;而对象集合的抽象又重要于表和行。
一 安装 SQLAlchemy
代码如下:
pip install sqlalchemy
导入如果没有报错则安装成功
导入如果没有报错则安装成功
代码如下:
>>> import sqlalchemy
>>> sqlalchemy.__version__
'0.9.1'
>>>
>>> sqlalchemy.__version__
'0.9.1'
>>>
二 使用 sqlalchemy对数据库操作
1. 定义元信息,绑定到引擎
代码如下:
(env)ghost@ghost-H61M-S2V-B3:~/project/flask/fsql$ python
Python 2.7.3 (default, Apr 10 2013, 05:13:16)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from sqlalchemy import *
>>> from sqlalchemy.orm import *
>>> engine = create_engine('sqlite:///./sqlalchemy.db', echo=True) # 定义引擎
>>> metadata = MetaData(engine) # 绑定元信息
>>>
(env)ghost@ghost-H61M-S2V-B3:~/project/flask/fsql$ python
Python 2.7.3 (default, Apr 10 2013, 05:13:16)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from sqlalchemy import *
>>> from sqlalchemy.orm import *
>>> engine = create_engine('sqlite:///./sqlalchemy.db', echo=True) # 定义引擎
>>> metadata = MetaData(engine) # 绑定元信息
>>>
2.创建表格,初始化数据库
代码如下:
>>> users_table = Table('users', metadata,
... Column('id', Integer, primary_key=True),
... Column('name', String(40)),
... Column('email', String(120)))
>>>
>>> users_table.create()
2014-01-09 10:03:32,436 INFO sqlalchemy.engine.base.Engine
CREATE TABLE users (
id INTEGER NOT NULL,
name VARCHAR(40),
email VARCHAR(120),
PRIMARY KEY (id)
)
2014-01-09 10:03:32,436 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:03:32,575 INFO sqlalchemy.engine.base.Engine COMMIT
>>>
>>> users_table = Table('users', metadata,
... Column('id', Integer, primary_key=True),
... Column('name', String(40)),
... Column('email', String(120)))
>>>
>>> users_table.create()
2014-01-09 10:03:32,436 INFO sqlalchemy.engine.base.Engine
CREATE TABLE users (
id INTEGER NOT NULL,
name VARCHAR(40),
email VARCHAR(120),
PRIMARY KEY (id)
)
2014-01-09 10:03:32,436 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:03:32,575 INFO sqlalchemy.engine.base.Engine COMMIT
>>>
执行上述代码,我们就创建 一个 users 表,有id, name, email 三个字段
代码如下:
(env)ghost@ghost-H61M-S2V-B3:~/project/flask/fsql$ sqlite3 sqlalchemy.db
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .tables
users
sqlite>
(env)ghost@ghost-H61M-S2V-B3:~/project/flask/fsql$ sqlite3 sqlalchemy.db
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> .tables
users
sqlite>
3. 基本操作,插入
如果已经table表已经存在, 第二次运行就不许要 create了, 使用 autoload 设置
代码如下:
>>> from sqlalchemy import *
>>> from sqlalchemy.orm import *
>>> engine = create_engine('sqlite:///./sqlalchemy.db', echo=True)
>>> metadata = MetaData(engine)
>>> users_table = Table('users', metadata, autoload=True)
2014-01-09 10:20:01,580 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("users")
2014-01-09 10:20:01,581 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:20:01,582 INFO sqlalchemy.engine.base.Engine PRAGMA foreign_key_list("users")
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine PRAGMA index_list("users")
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine ()
>>> users_table
Table('users', MetaData(bind=Engine(sqlite:///./sqlalchemy.db)), Column('id', INTEGER(), table=<users>, primary_key=True, nullable=False), Column('name', VARCHAR(length=40), table=<users>), Column('email', VARCHAR(length=120), table=<users>), schema=None)
>>>
书籍
>>> from sqlalchemy import *
>>> from sqlalchemy.orm import *
>>> engine = create_engine('sqlite:///./sqlalchemy.db', echo=True)
>>> metadata = MetaData(engine)
>>> users_table = Table('users', metadata, autoload=True)
2014-01-09 10:20:01,580 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("users")
2014-01-09 10:20:01,581 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:20:01,582 INFO sqlalchemy.engine.base.Engine PRAGMA foreign_key_list("users")
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine ()
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine PRAGMA index_list("users")
2014-01-09 10:20:01,583 INFO sqlalchemy.engine.base.Engine ()
>>> users_table
Table('users', MetaData(bind=Engine(sqlite:///./sqlalchemy.db)), Column('id', INTEGER(), table=<users>, primary_key=True, nullable=False), Column('name', VARCHAR(length=40), table=<users>), Column('email', VARCHAR(length=120), table=<users>), schema=None)
>>>
实例化一个插入句柄
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