python 持久化存储

anydbm模块

 1 import anydbm
 2  db = anydbm.open("1_dbm", "c")
 3  # Add an item.
 4  db["www.python.org"] = "Python home page"
 5  for i in range(100):
 6      db[str(i)] = str(i)
 7  #Keys and values must always be strings
 8  # db["number"] = 1    # raise an error
 9  print db["www.python.org"]
10  # Close and save to disk.
11  db.close()
12  
13  import anydbm
14  
15  db = anydbm.open("1_dbm", "r")
16  
17  print db["www.python.org"]
18  
19  # the size of 1_dbm.dat would not get small after delete some items
20  for i in range(50):
21      del db[str(i)]
22  
23  print db["51"]

marshal模块 

 1 # -*- coding: cp936 -*-
 2 import marshal
 3 """
 4 1仅支持基本数据类型 dictionary, list, tuple, numbers, string
 5 2不保证不用python版本之间的兼容
 6 3帮助文档中指出dump函数的需要文件对象必须以二进制“wb”，“rb”的形式读写（不用b好像也行）
 7 """
 8 data = {12 : "twelve", "feep" : list("test"), 1.23 : 4 + 5j, (1, 2, 3) : u"unicode"}
 9 
10 f = open("2_ps_marshal.dat", "wb")
11 
12 marshal.dump(data, f)
13 marshal.dump("a string type", f)
14 
15 f.close()
16 
17 #another file
18 
19 import marshal
20 
21 f = open("2_ps_marshal.dat", "r")
22 
23 a = marshal.load(f)
24 b = marshal.load(f)
25 
26 print a
27 print b
28 
2

  

[c]pickle模块

 

 1 import cPickle
 2 
 3 data = {12 : "twelve", "feep" : list("test"), 1.23 : 4 + 5j, (1, 2, 3) : u"unicode"}
 4 
 5 
 6 """dumps  protocol/version 参数：
 7 Protocol version 0 is the original ASCII protocol and is backwards compatible with earlier versions of Python.
 8 Protocol version 1 is the old binary format which is also compatible with earlier versions of Python.
 9 Protocol version 2 was introduced in Python 2.3. It provides much more efficient pickling of new-style classes.
10 """
11 
12 text = cPickle.dumps(data, 0)
13 print "protocal is 0", text
14 
15 text = cPickle.dumps(data, 1)
16 print "protocal is 1", text
17 
18 text = cPickle.dumps(data, 2)
19 print "protocal is 2", text
20 
21 str = cPickle.loads(text)
22 
23 print str
24 
25 
26 #another file
27 #use gzip module to compress the serialized file
28 #-*- coding:cp936 -*-
29 
30 import cPickle, gzip
31 
32 def save(filename, *objects):
33     """将对象存为压缩过的磁盘文件"""
34     f = gzip.open(filename, "wb")
35     [cPickle.dump(obj, f, protocol=2) for obj in objects]
36     f.close()
37 
38 def load(filename):
39     """从压缩的磁盘文件中载入对象"""
40     f = gzip.open(filename, "rb")
41     while True:
42     try : 
43         yield cPickle.load(f)
44     except EOFError: 
45         break
46     f.close()
47 
48 if __name__ == "__main__":
49     f = open("3_largeFile.txt", "rb")
50     save("3_compressed.dat", f.read())
51     gen = load("3_compressed.dat")
52     content = gen.next()
53     print content
54 
55

 

 

shelve模块

 1 import shelve
 2  
 3  she = shelve.open("4_try.she", "c")
 4  
 5  for c in "spam" : 
 6      she[c] = {c : 23}
 7  
 8  print she
 9  
10  for c in she.keys():
11      print c, she[c]
12  
13  she.close()
14  
15  
16  #another file
17  #how to modify the value
18  import shelve
19  
20  she = shelve.open("4_try.she", "c")
21  #she = shelve.open("try.she", "c", writeback = True)
22  
23  print she
24  
25  print "original she[\"p\"] :", she["p"]
26  
27  she["p"]["p"] = 99 # would not change the original she["p"] value
28  print "method one : ", she["p"]
29  
30  a = she["p"]    # one of the methods to change the original value 
31  a["p"] = 99
32  she["p"] = a
33  print "method two : ", she["p"]

MySQLdb模块(选择合适的版本下载)

 1 import MySQLdb
 2 import pprint
 3 
 4 con = MySQLdb.connect(host="127.0.0.1", port=3306, user="root", passwd="11", db="hellomysql")
 5 
 6 cursor = con.cursor()
 7 
 8 sql = "SELECT * FROM pet"
 9 
10 cursor.execute(sql)
11 
12 pprint.pprint(cursor.description)
13 
14 results = cursor.fetchall()
15 
16 pprint.pprint(results)
17 
18 print type(results)
19 
20

 

 

访问MySQL存储过程 （访问带传出参数的sp时，方法有点，待改进）

 

 1 import MySQLdb
 2 import pprint
 3 
 4 con = MySQLdb.connect(host="127.0.0.1", port=3306, user="root", passwd="11", db="hellomysql")
 5 
 6 cursor = con.cursor()
 7 cursor.nextset()
 8 param2=list() 
 9 param3 = list()
10 
11 t1 = cursor.callproc("Proc_test", ("snake", param2, param3))
12 cursor.execute("select @_Proc_test_1, @_Proc_test_2")
13 
14 print param2
15 
16 pprint.pprint(t1)
17 
18

访问SQL数据库(下载pyodbc)

#-*- coding:cp936 -*-
 2 import pyodbc
 3 import pprint
 4 
 5 
 6 conn = pyodbc.connect("DSN=yourdsnname")
 7 #the following sentence can work as well
 8 #conn = pyodbc.connect("DRIVER={SQL Server};SERVER=servername;DATABASE=dbname;UID=sa;PWD=sa") 
 9 
10 c = conn.cursor()
11 
12 sql = "select * From AdTypeTree"
13 
14 c.execute(sql)
15 
16 rows = c.fetchall()
17 
18 pprint.pprint(rows)
19 print rows[0][1] 1 #-*- coding:cp936 -*-
 2 import pyodbc
 3 import pprint
 4 
 5 
 6 conn = pyodbc.connect("DSN=yourdsnname")
 7 #the following sentence can work as well
 8 #conn = pyodbc.connect("DRIVER={SQL Server};SERVER=servername;DATABASE=dbname;UID=sa;PWD=sa") 
 9 
10 c = conn.cursor()
11 
12 sql = "select * From AdTypeTree"
13 
14 c.execute(sql)
15 
16 rows = c.fetchall()
17 
18 pprint.pprint(rows)
19 print