MsAccess for Rails: Here's your rough connector.

Ok, after using this for quite a hefty project and it worked for all that I needed it for, I thought it has enough potential to be beneficial to someone, and I might as well let it out of the bag for that person.

Download the file at http://gist.github.com/raw/102271/40dc4d1de9135a94d7a8961d8f75907ad7b95de8/msaccess_adapter.rb. To install, plop it into your rails' connection_adapters directory (vendor / rails / activerecord / lib / active_record / connection_adapters).
Config should look like this:

development:
  adapter: msaccess
  database: C:\path\to\access_file.mdb

Of course, using Microsoft Access files from legacy (non-rails) apps often includes several database files. I recommend using the 'use_db' plugin. I made a modification to make it easier to use -- open up lib/use_db.rb within the plugin and replace this method: http://pastie.caboo.se/78705. Then simply put in your model:

use_db :database => 'C:\path\to\other.mdb'

Remember also, when using Access databases, most of the time you will be using a database that was created for another purpose - probably with a different table naming scheme and a primary key that is not named 'id'. Therefore, you'll have to make good use of set_table_name and set_primary_key in order to have the right handles on things. Another couple points: Sometimes a table may not have a good primary key - as long as you're just reading data from it you can get by without any primary key at all - just don't reference a primary key and rails is happy as a clam! And if your primary key ends up being something other than an integer (for example, part numbers that aren't quite autoincrementing, and include characters), Rails and the msaccess_adapter are okay with that, just be careful to set your id before you create records. (That reminds me, I think I made a couple modifications to AR::Base to better accomodate these id things - if anyone comes up with problems related to this, I'll remember what those are and add them in)

This only works on Windows, because it uses ADO through WIN32OLE. I guess I must say, it requires the win32ole gem too. Just "sudo gem install win32ole" if you don't have it already. It comes prepackaged with InstantRails (a nice prepackaged rails environment for windows).

Last words on the adapter:

PLEASE PLEASE contribute. If you fix the binary_to_string / string_to_binary functions, let me know and I will integrate your fix. That goes for anything else. Let me know what's broken, but don't rely on me to fix it. I will fix things as I need them fixed for my own applications, and if you fix something, please submit it to me (patches@behindlogic.com) for the good of everyone who wants to use this adapter. Thanks!