In Python 2.7.6 can't find any way to close MSI database after finish working with it.
As a result database is locked and can't be opened by any other application until Python process is finished.

    import msilib
    db = msilib.OpenDatabase('test.msi', msilib.MSIDBOPEN_TRANSACT)
    view = db.OpenView("SELECT File, Component_, FileName FROM File")
    view.Execute(None)
    r1 = view.Fetch()
    r1.SetString(3,"test.txt")
    view.Modify(msilib.MSIMODIFY_UPDATE, r1)
    view.Close()
    db.Commit()
    del db
    db2 = msilib.OpenDatabase('test.msi', msilib.MSIDBOPEN_TRANSACT)

    MSIError: 1: 2203 2: test.msi 3: -2147287008

Sorry folks I can't try this myself as I'm not running 2.7 and I don't know how to create the test.msi file.

This is still present in Python 3.5. There is no way to unlock the MSI file without killing the Python process first.

Guessing the msiobj_close function in PC/_msi.c ought to be exposed. 

Patches welcome.

I will prefix this by saying that I have not contributed to the Python source before and this patch is probably wrong, but here is my attempt at a fix.

Thanks for the patch, 12345. Steve knows better, but I think the method should be named "Close" instead of "close" like _msi.View's Close method.

Also, I couldn't apply your patch:

$ hg imp http://bugs.python.org/file45971/Add_ability_to_close_MSI_database_.patch
applying http://bugs.python.org/file45971/Add_ability_to_close_MSI_database_.patch
unable to find '_msi.c' for patching
patching file _msi.c
2 out of 2 hunks FAILED -- saving rejects to file _msi.c.rej
abort: patch failed to apply

You may want to read https://docs.python.org/devguide/patch.html for details about creating a patch.

The method is now capitalized. Unfortunately, none of the methods are compliant with PEP formatting, but it's far too late to do anything about that.

xoviat, would you like to send your patch as a pull request on GitHub? It would be nice to add a simple test that the new Close() works correctly. I can do that if you don't have time, thank you!

Steve, can we apply this to bugfix branches?

Unfortunately, this issue has taken on a much lower importance for me, and
as such, I won't be able to address it. Sorry about that.

2017-10-26 0:01 GMT-05:00 Berker Peksag <report@bugs.python.org>:

>
> Berker Peksag <berker.peksag@gmail.com> added the comment:
>
> xoviat, would you like to send your patch as a pull request on GitHub? It
> would be nice to add a simple test that the new Close() works correctly. I
> can do that if you don't have time, thank you!
>
> Steve, can we apply this to bugfix branches?
>
> ----------
> versions:  -Python 3.5
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue20486>
> _______________________________________
>

New changeset a935654f0613640535fbf0ba190f81d02a63d35c by Berker Peksag in branch 'master':
bpo-20486: Implement Database.Close() method in msilib (GH-4141)
https://github.com/python/cpython/commit/a935654f0613640535fbf0ba190f81d02a63d35c

Thank you, all. The OP's snippet should work now:

>>> import msilib as m
>>> db = m.OpenDatabase('py33.msi', m.MSIDBOPEN_TRANSACT)
>>> db.Commit()
>>> db2 = m.OpenDatabase('py33.msi', m.MSIDBOPEN_TRANSACT)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
_msi.MSIError: 1: 2203 2: py33.msi 3: -2147287008
>>> db.Close()
>>> db2 = m.OpenDatabase('py33.msi', m.MSIDBOPEN_TRANSACT)

I didn't backport this to bugfix branches since we added a new public function to the API.