title: Python pip unable to locate pyodbc
body: <p>Using virtualenv and just trying to install pyodbc. All resources I can find claim this should be extremely straightforward. After all the basic installs of MySQL, etc., just do:</p>
  
  <pre><code>pip install pyodbc
  </code></pre>
  
  <p>However, I am seeing a very strange error. It has nothing (as far as I can tell) to do with missing libraries, and after Googling for this sort of error for a long time, I can't find anything constructive on it at all.</p>
  
  <pre><code>(local-dev)espears@espears-w ~ $ pip install pyodbc
  Downloading/unpacking pyodbc
    Could not find any downloads that satisfy the requirement pyodbc
    Some externally hosted files were ignored (use --allow-external pyodbc to allow).
  Cleaning up...
  No distributions at all found for pyodbc
  Storing debug log for failure in /home/espears/.pip/pip.log
  </code></pre>
  
  <p>So I tried with the "allow-external" option and it does not help:</p>
  
  <pre><code>(local-dev)espears@espears-w ~ $ pip install --allow-external pyodbc
  You must give at least one requirement to install (see "pip help install")
  </code></pre>
  
  <p>But the help documentation makes it appear that I am using this option correctly, e.g. from the output of running <code>pip help install</code>:</p>
  
  <pre><code>Package Index Options:
  
  ...
  
    --allow-external &lt;package&gt;  Allow the installation of externally hosted files
  </code></pre>
  
  <p>Here's the result in the PIP log file:</p>
  
  <pre><code>(local-dev)espears@espears-w ~ $ cat /home/espears/.pip/pip.log
  Downloading/unpacking pyodbc
    Getting page https://pypi.python.org/simple/pyodbc/
    URLs to search for versions for pyodbc:
    * https://pypi.python.org/simple/pyodbc/
    Analyzing links from page https://pypi.python.org/simple/pyodbc/
      Skipping link http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/); not a file
      Skipping link http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/); not a file
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Not searching http://code.google.com/p/pyodbc/downloads/list (from https://pypi.python.org/simple/pyodbc/) for files because external urls are disallowed.
    Could not find any downloads that satisfy the requirement pyodbc
    Some externally hosted files were ignored (use --allow-external pyodbc to allow).
  Cleaning up...
    Removing temporary dir /home/espears/.virtualenvs/local-dev/build...
  No distributions at all found for pyodbc
  Exception information:
  Traceback (most recent call last):
    File "/home/espears/.virtualenvs/local-dev/local/lib/python2.7/site-packages/pip/basecommand.py", line 122, in main
      status = self.run(options, args)
    File "/home/espears/.virtualenvs/local-dev/local/lib/python2.7/site-packages/pip/commands/install.py", line 270, in run
      requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
    File "/home/espears/.virtualenvs/local-dev/local/lib/python2.7/site-packages/pip/req.py", line 1157, in prepare_files
      url = finder.find_requirement(req_to_install, upgrade=self.upgrade)
    File "/home/espears/.virtualenvs/local-dev/local/lib/python2.7/site-packages/pip/index.py", line 285, in find_requirement
      raise DistributionNotFound('No distributions at all found for %s' % req)
  DistributionNotFound: No distributions at all found for pyodbc
  </code></pre>
  
  <p>It makes it seem that if I can just get the <code>--allow-external</code> option to work, it will work because it clearly sees the common location for getting pyodbc.</p>
  
  <p>But I am puzzled why this is needed at all, when virtually all references to installing pyodbc do not need to go out of the way to enable external links. I've also been installing many packages all day today, with few issues and certainly not encountering this <code>allow-external</code> need in any other case.</p>
  
  <p>I am using pip version 1.5 with Python 2.7.3 on Ubuntu 12.04.</p>