Wie Python MySQL binäre Streams speichert

import MySQLdb   
  
class BlobDataTestor:   
    def __init__ (self):   
        self.conn = MySQLdb.connect(host='localhost',user='',passwd='',db='0')   
  
    def __del__ (self):   
        try:   
            self.conn.close()   
        except :   
            pass    
  
  
    def closedb(self):   
        self.conn.close()   
  
    def setup(self):   
        cursor = self.conn.cursor()   
        cursor.execute( """  
            CREATE TABLE IF NOT EXISTS `Dem_Picture` (  
            `ID` int(11) NOT NULL auto_increment,  
            `PicData` mediumblob,  
            PRIMARY KEY (`ID`)  
            ) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=4 ;  
            """)   
  
  
  
    def teardown(self):   
        cursor = self.conn.cursor()   
        try:   
            cursor.execute( "Drop Table Dem_Picture" )   
        except:   
            pass    
        # self.conn.commit()    
  
    def testRWBlobData(self):    
    # 读取源图片数据                  
        f = open( "C:\\11.jpg" , "rb" )   
        b = f.read()   
        f.close()   
  
    # 将图片数据写入表    
        cursor = self.conn.cursor()   
        cursor.execute( "INSERT INTO Dem_Picture (PicData) VALUES (%s)" , (MySQLdb.Binary(b)))   
    # self.conn.commit()    
  
    # 读取表内图片数据，并写入硬盘文件    
        cursor.execute( "SELECT PicData FROM Dem_Picture ORDER BY ID DESC limit 1" )   
        d = cursor.fetchone()[0]   
        cursor.close()   
  
        f = open( "C:\\22.jpg" , "wb" )   
        f.write(d)   
        f.close()   
  
# 下面一句的作用是：运行本程序文件时执行什么操作  
if __name__ == "__main__":   
  
    test = BlobDataTestor()   
  
    try:   
        test.setup()   
        test.testRWBlobData()   
        test.teardown()   
    finally:   
        test.closedb()