弓在箭要射出之前，低声对箭说道，“你的自由是我的”。Schema如箭，弓似Python，选择Python，是Schema最大的自由。而自由应是一个能使自己变得更好的机会。
㈠ MySQLdb部分
mysql> use sakila; mysql> desc actor; +-------------+----------------------+------+-----+-------------------+-----------------------------+ | Field | Type | Null | Key | Default | Extra | +-------------+----------------------+------+-----+-------------------+-----------------------------+ | actor_id | smallint(5) unsigned | NO | PRI | NULL | auto_increment | | first_name | varchar(45) | NO | | NULL | | | last_name | varchar(45) | NO | MUL | NULL | | | last_update | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP | +-------------+----------------------+------+-----+-------------------+-----------------------------+ 4 rows in set (0.00 sec)
[root@DataHacker ~]# cat dbapi.py #!/usr/bin/env ipython #coding = utf-8 #Author: linwaterbin@gmail.com #Time: 2014-1-29 import MySQLdb as dbapi USER = 'root' PASSWD = 'oracle' HOST = '127.0.0.1' DB = 'sakila' conn = dbapi.connect(user=USER,passwd=PASSWD,host=HOST,db=DB)
[root@DataHacker ~]# cat QueryColumnMetaData.py #!/usr/bin/env ipython from dbapi import * cur = conn.cursor() statement = """select * from actor limit 1""" cur.execute(statement) print "output column metadata....." print for record in cur.description: print record cur.close() conn.close()
1.）调用execute()之后，cursor应当设置其description属性
2.）是个tuple，共7列：列名、类型、显示大小、内部大小、精度、范围以及一个是否接受null值的标记
[root@DataHacker ~]# chmod +x QueryColumnMetaData.py
[root@DataHacker ~]# ./QueryColumnMetaData.py
output column metadata.....
('actor_id', 2, 1, 5, 5, 0, 0)
('first_name', 253, 8, 45, 45, 0, 0)
('last_name', 253, 7, 45, 45, 0, 0)
('last_update', 7, 19, 19, 19, 0, 0)
In [1]: from dbapi import * In [2]: cur = conn.cursor() In [3]: v_sql = "select actor_id,last_name from actor limit 2" In [4]: cur.execute(v_sql) Out[4]: 2L In [5]: results = cur.fetchone() In [6]: print results[0] 58 In [7]: print results[1] AKROYD
In [2]: import MySQLdb.cursors In [3]: import MySQLdb In [4]: conn = MySQLdb.connect(user='root',passwd='oracle',host='127.0.0.1',db='sakila',cursorclass=MySQLdb.cursors.DictCursor) In [5]: cur = conn.cursor() In [6]: v_sql = "select actor_id,last_name from actor limit 2" In [7]: cur.execute(v_sql) Out[7]: 2L In [8]: results = cur.fetchone() In [9]: print results['actor_id'] 58 In [10]: print results['last_name'] AKROYD
㈡ SQLAlchemy--SQL炼金术师
SQLAlchemy连接模块： [root@DataHacker Desktop]# cat sa.py import sqlalchemy as sa engine = sa.create_engine('mysql://root:oracle@127.0.0.1/testdb',pool_recycle=3600) metadata = sa.MetaData()
In [3]: t = Table('t',metadata, ...: Column('id',Integer), ...: Column('name',VARCHAR(20)), ...: mysql_engine='InnoDB', ...: mysql_charset='utf8' ...: ) In [4]: t.create(bind=engine)
有2种方式，其一： In [5]: t.drop(bind=engine,checkfirst=True) 另一种是： In [5]: metadata.drop_all(bind=engine,checkfirst=True)，其中可以借助tables属性指定要删除的对象
3 .1 primary key 下面2种方式都可以，一个是列级，一个是表级 In [7]: t_pk_col = Table('t_pk_col',metadata,Column('id',Integer,primary_key=True),Column('name',VARCHAR(20))) In [8]: t_pk_col.create(bind=engine) In [9]: t_pk_tb = Table('t_pk_01',metadata,Column('id',Integer),Column('name',VARCHAR(20)),PrimaryKeyConstraint('id','name',name='prikey')) In [10]: t_pk_tb.create(bind=engine) 3.2 Foreign Key In [13]: t_fk = Table('t_fk',metadata,Column('id',Integer,Fore