python sqlite3 .executemany() 与命名占位符？

Question

这行得通：

ss = 'insert into images (file_path) values(?);'
dddd = (('dd1',), ('dd2',))
conn.executemany(ss, dddd)

但事实并非如此：

s = 'insert into images (file_path) values (:v)'
ddddd = ({':v': 'dd11'}, {':v': 'dd22'})
conn.executemany(s, ddddd)
Traceback (most recent call last):
  File "/Users/Wes/.virtualenvs/ppyy/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 3035, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-31-a999de59f73b>", line 1, in <module>
    conn.executemany(s, ddddd)
ProgrammingError: You did not supply a value for binding 1.

我想知道是否可以将命名参数与 executemany 一起使用，如果可以，如何使用。

第 11.13.3 节中的 documentation 一般谈论参数，但没有讨论为其他风格的 .executexxx() 描述的两种参数样式。

我查看了与 executemany 无关的 Python sqlite3 execute with both named and qmark parameters。

Answer 1

source 表明execute() 只是构造了一个单元素列表并调用executemany()，所以问题不在于executemany() 本身；相同的调用失败，execute():

>>> conn.execute('SELECT :v', {':v': 42})
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
sqlite3.ProgrammingError: You did not supply a value for binding 1.

如Python documentation所示，命名参数不包含冒号：

# And this is the named style:
cur.execute("select * from people where name_last=:who and age=:age", {"who": who, "age": age})

所以你必须使用ddddd = ({'v': 'dd11'}, {'v': 'dd22'})。

Answer 2

: 不是参数名称的一部分。

>>> s = 'insert into images (file_path) values (:v)'
>>> ddddd = ({'v': 'dd11'}, {'v': 'dd22'})
>>> conn.executemany(s, ddddd)
<sqlite3.Cursor object at 0x0000000002C0E500>
>>> conn.execute('select * from images').fetchall()
[(u'dd11',), (u'dd22',)]