Q:

how to have svn fetch a file from another directory on updates?

I have two repository folder. One in which the build.dll is set.
There is another folder which needs this dll up to date. What I'd like to do is when I update the second directory on my computer, it would fetch the build.dll from the other one. So no physical copy in the second directory.
We have Windows 7 at work.

A:

Subversion calls these types of relationships "externals".  You just need to set the svn:externals property on the second directory so that SVN will pull down the external file when the second directory is updated.
To set this property, run a command similar to this (on Windows):
svn propset svn:externals "^/trunk/path/to/build.dll build.dll" your/second/directory

Or, if you're using TortoiseSVN, the built-in editor is quite a bit more user-friendly.  See details here.

