The basic software doesn't link to any database directly, but....
1) It may depend on what purpose you want to 'link' - e.g. you could layer a generic API or OR Reconciliation service over the top of the database to be able to use data from the database to enhance data you already have in OR
3) At least one OpenRefine extension I know of uses OpenRefine to upload data directly to a database and draws information down from the database to help data manipulation in OR - have a look at the OR forks and extensions listed on
http://openrefine.org/download.html - some of these may have database integration (the one I know of is the GOKb extension)
Owen