Python实现数据库编程方法详解

Column descriptions:
  ('country_id', 'NUMBER', 12, 10, 10, 0, 0)
  ('name', 'STRING', 45, 45, 0, 0, 0)
  ('insert_change_date', 'DATE', 19, 19, 0, 0, 1)
First result row:
  (24L, 'ARGENTINA', <DbiDate object at 7f1c80>)
Date conversions:
  standard string:   Fri Dec 19 01:51:53 1997
  seconds since epoch:  882517913.0
  time tuple:    (1997, 12, 19, 1, 51, 53, 4, 353, 0)
  user defined:    19 December 1997

大家也可以去http://www.python.org/windows/win32/odbc.html看看,那儿有两个Hirendra Hindocha写的例子,还不错.

注意, 这个例子中,结果值被转化为Python对象了.时间被转化为一个dbiDate对象.这里会有一点限制,因为dbiDate只能表示UNIX时间(1 Jan 1970 00:00:00 GMT)之后的时间.如果你想获得一个更早的时间,可能会出现乱码甚至引起系统崩溃.*_*

方法三: 使用 calldll模块

(Using this module, you can use ODBC API directly. But now the python version is 2.1, and I don't know if other version is compatible with it. 老巫:-)

Sam Rushing的calldll模块可以让Python调用任何动态连接库里面的任何函数,厉害吧?哈.其实,你能够通过直接调用odbc32.dll里面的函数操作ODBC.Sam提供了一个包装模块odbc.py,就是来做这个事情的.也有代码来管理数据源,安装ODBC,实现和维护数据库引擎 (Microsoft Access).在那些演示和例子代码中,还有一些让人侧目的好东东,比如cbdemo.py,有一个信息循环和窗口过程的Python函数!

[你可以到Sam's Python Software去找到calldll的相关连接,那儿还有其他好多有趣的东西]

下面是安装CALLDLL包的步骤:

1. 安装PYTHON软件包(到现在为止最多支持2.1版本)

2. 下载calldll-2001-05-20.zip:

ftp://squirl.nightmare.com/pub/python/python-ext/calldll-2001-05-20.zip

3. 在LIB路径下面创建一个新路径比如说:

c:/Program Files/Python/lib/caldll/

4. 在原目录下解压calldll.zip

5. 移动calldll/lib/中所有的文件到上面一个父目录(calldll)里面,删除子目录(lib)

6. 在CALL目录里面生成一个file __init__.py文件,象这样:

# File to allow this directory to be treated as a python 1.5
package.

7. 编辑calldll/odbc.py:

在"get_info_word"和"get_info_long"里面,改变"calldll.membuf"为"windll.membuf"

下面是一个怎么使用calldll的例子:

from calldll import odbc
dbc = odbc.environment().connection() # create connection
dbc.connect('sample', 'monty', 'spam') # connect to db
# alternatively, use full connect string:
# dbc.driver_connect('DSN=sample;UID=monty;PWD=spam')
print 'DBMS: %s %s/n' % ( # show DB information
  dbc.get_info(odbc.SQL_DBMS_NAME),
  dbc.get_info(odbc.SQL_DBMS_VER)
  )
result = dbc.query( # execute query & return results
  """
  SELECT country_id, name, insert_change_date
  FROM country
  ORDER BY name
  """
  )
print 'Column descriptions:' # show column descriptions
for col in result[0]:
  print ' ', col
print '/nFirst result row:/n ', result[1] # show first result row

DBMS: Oracle 07.30.0000
Column descriptions:
  ('COUNTRY_ID', 3, 10, 0, 0)
  ('NAME', 12, 45, 0, 0)
  ('INSERT_CHANGE_DATE', 11, 19, 0, 1)
First result row:
  ['24', 'ARGENTINA', '1997-12-19 01:51:53']

>>> import win32com.client
>>> conn = win32com.client.Dispatch(r'ADODB.Connection')
>>> DSN = 'PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=C:/MyDB.mdb;'
>>> conn.Open(DSN)

>>> rs = win32com.client.Dispatch(r'ADODB.Recordset')
>>> rs_name = 'MyRecordset'
>>> rs.Open('[' + rs_name + ']', conn, 1, 3)

>>> flds_dict = {}
>>> for x in range(rs.Fields.Count):
...  flds_dict[x] = rs.Fields.Item(x).Name

>>> print rs.Fields.Item(1).Type
202 # 202 is a text field
>>> print rs.Fields.Item(1).DefinedSize
50 # 50 Characters

>>> rs.AddNew()
>>> rs.Fields.Item(1).Value = 'data'
>>> rs.Update()

>>> x = rs.Fields.Item(1).Value
>>> print x
'data'

>>> rs.AddNew()
>>> x = rs.Fields.Item('Auto_Number_Field_Name').Value 
# x contains the AutoNumber
>>> rs.Fields.Item('Field_Name').Value = 'data'
>>> rs.Update()

>>> oCat = win32com.client.Dispatch(r'ADOX.Catalog')
>>> oCat.ActiveConnection = conn
>>> oTab = oCat.Tables
>>> for x in oTab:
...  if x.Type == 'TABLE':
...   print x.Name

>>> conn = win32com.client.Dispatch(r'ADODB.Connection')
>>> DSN = 'PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=C:/MyDB.mdb;'
>>> sql_statement = "INSERT INTO [Table_Name]
([Field_1], [Field_2]) VALUES ('data1', 'data2')"
>>> conn.Open(DSN)
>>> conn.Execute(sql_statement)
>>> conn.Close()

>>> # See example 3 above for the set-up to this
>>> rs.MoveFirst()
>>> count = 0
>>> while 1:
...  if rs.EOF:
...   break
...  else:
...   count = count + 1
...   rs.MoveNext()

>>> rs.Cursorlocation = 3 # don't use parenthesis here
>>> rs.Open('SELECT * FROM [Table_Name]', conn) # be sure conn is open
>>> rs.RecordCount # no parenthesis here either
186