[英]Closing cursor and connection with Python and MySQLdb
I have a simple web.py-based app that uses MySQLdb. 我有一个简单的基于web.py的应用程序,它使用MySQLdb。 I have a class that handles database operations like so:
我有一个类来处理数据库操作,如下所示:
class db():
def __init__(self):
db = MySQLdb.connect(host='mysql.server', user='user', passwd='pass', db='app')
self.cur = db.cursor()
def get_data(self):
sql = "SELECT * FROM foobar"
self.cur.execute(sql)
rs = self.cur
r.fetchall()
return rs
I instantiate the class like so DB = db()
. 我将类实例化为
DB = db()
。 Then, in another class, I will refer to it. 然后,在另一个课程中,我将参考它。
class bleh()
def blarg():
DB.get_data()
With something like this, where would I close the cursor and connection? 有了这样的东西,我会在哪里关闭光标和连接? Or am I approaching this completely wrong?
或者我接近这个完全错误?
db.close()
for connection and cur.close()
for cursor. 用于连接的
db.close()
和用于游标的cur.close()
。
http://mysql-python.sourceforge.net/MySQLdb.html http://mysql-python.sourceforge.net/MySQLdb.html
EDIT: 编辑:
But if it give it a bit thought - you won't need to close cursor. 但如果它考虑一下 - 你将不需要关闭光标。 Python closes the cursor once the variable is destroyed, so when the instance of your class does not exist anymore -- cursor will be closed.
一旦变量被销毁,Python就会关闭游标,所以当你的类的实例不再存在时 - 游标将被关闭。
First of all use different names for class-name and variable as you have used same name ('db') for class-name and connection as well. 首先为类名和变量使用不同的名称,因为您对类名和连接使用了相同的名称('db')。
Next, you need to define conn (in your question db
line no 3) as self.conn
. 接下来,您需要将conn(在您的问题
db
第3行)定义为self.conn
。
import MySQLdb
导入MySQLdb
class db():
class db():
def __init__(self): self.conn = MySQLdb.connect(host='mysql.server', user='user', passwd='pass', db='app') self.cur = self.conn.cursor() def get_data(self): sql = "SELECT * FROM test" self.cur.execute(sql) rs = self.cur rs.fetchall() return rs
class bleh()
def blarg():
data = DB.get_data()
DB.cur.close()
DB.conn.close()
Note: If you have multiple functions in class bleh to get data from database make sure that you close cursor and connection in function, which is to called in last. 注意:如果在类bleh中有多个函数从数据库获取数据,请确保在函数中关闭游标和连接,这在最后调用。 Or you may have a seperate function, which closes cursor and connection.
或者你可能有一个单独的功能,它关闭光标和连接。
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