SQLObject和SQLAlchemy都是Python語言下的ORM(對象關系映射)解決方案,其中SQLAlchemy被認為是Python下事實上的ORM標準。當然,兩者都很優秀。
一、安裝
sudo pip install SQLObject
使用SQLObject操作mysql時候報錯ImportError: No module named MySQLdb,那便安裝MySQLdb:
sudo pip install MySQL-python
沒想到又報錯了:
_mysql.c:29:20: fatal error: Python.h: No such file or directory
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
解決方法:
sudo apt-get install libmysqlclient-dev python-dev
二、使用其創建表將mysql默認存在的test數據庫的編碼改為utf-8。
#-*-encoding:utf-8-*-
from sqlobject import *
uri = r'mysql://root:passwd@127.0.0.1/test?charset=utf8'
sqlhub.processConnection = connectionForURI(uri)
class User(SQLObject):
name = StringCol(length=10, notNone=True)
email = StringCol(length=20, notNone=True)
password = StringCol(length=20, notNone=True)
User.createTable()
運行后,會看到test數據庫下出現表user,我們使用show create table user;查看user表的創建語句,結果如下:
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(10) NOT NULL,
`email` varchar(20) NOT NULL,
`password` varchar(20) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
三、添加/刪除記錄
現在我們嘗試著添加和刪除記錄。
user1 = User(name='user1',email='user1@163.com',password='111')
user2 = User(name='user2',email='user2@163.com',password='222')
運行后,使用select * from user能看到這兩個記錄:
mysql> select * from user;
+----+-------+---------------+----------+
| id | name | email | password |
+----+-------+---------------+----------+
| 1 | user1 | user1@163.com | 111 |
| 2 | user2 | user2@163.com | 222 |
+----+-------+---------------+----------+
2 rows in set (0.00 sec)
刪除數據
u2 = User.get(2)
print User.delete(u2.id)
四、查詢記錄
通過id獲取數據:
u1 = User.get(1)
u1_1 = User.get(1)
u2 = User.get(2)
print id(u1), u1
print id(u1_1), u1_1
print id(u2), u2
輸出結果:
23864656
23864656
23930512
由于id(u1)和id(u1_1)是相等的,所以u1和u1_1是內容一致,這樣做可以減少內存使用。可以在連接數據庫時候設置參數,禁止該方式。根據name進行查詢:
users = User.select(User.q.name=="user1")
print users
print list(users)
輸出結果:
SELECT user.id, user.name, user.email, user.password FROM user WHERE ((user.name) = ('user1'))
[]
模糊查詢:
users = User.select(User.q.name.startswith('u'))
print users
print list(users)
users = User.select(User.q.name.contains('ser1'))
print users
print list(users)
運行結果:
SELECT user.id, user.name, user.email, user.password FROM user WHERE (user.name LIKE ('u%') ESCAPE '//')
[, ]
SELECT user.id, user.name, user.email, user.password FROM user WHERE (user.name LIKE ('%ser1%') ESCAPE '//')
[]
一對多映射
我們新建一個表,保存user中每個用戶的編寫的文章:
class User(SQLObject):
name = StringCol(length=10, notNone=True)
email = StringCol(length=20, notNone=True)
password = StringCol(length=20, notNone=True)
class Article(SQLObject):
title = StringCol(length=100, notNone=True)
content = StringCol(notNone=True)
user = ForeignKey('User')
Article.createTable()
運行后,使用show create table article查看創建語句:
CREATE TABLE `article` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`title` varchar(100) NOT NULL,
`content` text NOT NULL,
`user_id` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `article_user_id_exists` (`user_id`),
CONSTRAINT `article_user_id_exists` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
添加數據:
u1 = User.get(1)
a1 = Article(title='title1',content='你好',user=u1)
查詢數據:
u1 = User.get(1)
a1 = Article.select(Article.q.user == u1)
print a1
print list(a1)
print list(a1)[0].content
這種方式也可以:
a1 = Article.select(Article.q.userID == 1)
print a1
print list(a1)
print list(a1)[0].content
運行結果:
SELECT article.id, article.title, article.content, article.user_id FROM article WHERE ((article.user_id) = (1))
[<Article title='title1'>]
你好