SVN：更新时本地忽略文件

I would like to delete/change some file in my local SVN repository and then SVN not to try update them while doing update (just for me on my local machine). I have to test one specific bug with this customers data, but it 12GB of them. So I would like to exchange some of DB file with dummy (empty with correct structure (MDB)) files. And I want SVN to ignore these files while doing updates (especially not to bother me with conflicts).I would like to delete/change some file in my l