Python例程：使用adodbapi存取二进制数据

昨天尝试了adodbapi的常用操作，今天写一个存取二进制图片的程序试试，ado里面存取二进制数据还是要稍复杂点，不知道adodbapi表现又怎么样。

例程功能：

1. 新建一个测试表，用于存储图片数据

2. 读取源图片数据，插入一条记录到测试表

3. 读取新插入的表记录，将二进制字段数据写入到目标文件

4. 直接打开目标图片文件，看看内容是否与源图片一致

1#coding=utf-8
2
3import adodbapi

4class BlobDataTestor:
5    def __init__(self):
6     self.conn = None
7
8    def __del__(self):
9     try:
10         self.conn.close()
11     except:
12         pass
13
14    def connectdb(self, connectString):
15     self.conn = adodbapi.connect(connectString)
16
17    def closedb(self):
18     self.conn.close()
19
20    def setup(self):
21        cursor = self.conn.cursor()
22        cursor.execute("""
23            CREATE TABLE [Dem_Picture] (
24                [ID] [int] IDENTITY (1, 1) NOT NULL ,
25                [PicData] [image] NULL ,
26                CONSTRAINT [PK_Dem_Picture] PRIMARY KEY  CLUSTERED
27                (
28                    [ID]
29                )  ON [PRIMARY]
30            ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY];""")
31        #self.conn.commit()
32
33    def teardown(self):
34        cursor = self.conn.cursor()
35        try:
36            cursor.execute("Drop Table Dem_Picture")
37        except:
38            pass
39        #self.conn.commit()
40
41    def testRWBlobData(self):
42        #读取源图片数据
43        f = open("C:\\src.bmp", 'rb')
44        b = f.read()
45        f.close()
46
47        #将图片数据写入表
48        cursor = self.conn.cursor()
49        cursor.execute("INSERT INTO Dem_Picture (PicData) VALUES (?)", (adodbapi.Binary(b),))
50        #self.conn.commit()
51
52        #读取表内图片数据，并写入硬盘文件
53        cursor.execute("SELECT TOP 1 PicData FROM Dem_Picture ORDER BY ID DESC")
54        d = cursor.fetchone()[0]
55        cursor.close()
56
57        f = open("C:\\dst.bmp", "wb")
58        f.write(d)
59        f.close()
60
61
62if __name__ == "__main__":
63    test = BlobDataTestor()
64    test.connectdb("Provider=SQLOLEDB.1;Persist Security Info=True;Password=;User ID=sa;Initial Catalog=pubs;Data Source=.")
65    try:
66        test.setup()
67        test.testRWBlobData()
68        test.teardown()
69    finally:
70        test.closedb()
71