I just released the new version of the JIRA Database Values Plugin. It is now compatible with JIRA 5.1 and 5.2. Most notable change is that under the hood jQuery is used now instead of Scriptaculous.
See Atlassian Marketplace for the download.
The source code has also been migrated to the excellet Bitbucket service. Sources can be found at https://bitbucket.org/wimdeblauwe/jdvp and the documentation at the embedded wiki: https://bitbucket.org/wimdeblauwe/jdvp/wiki/Home
This version would not have been possible without the people that donated on GoFundMe so a big thank you to them all!
PS: One breaking change is that linking of multiple custom fields is no longer supported. It never worked really well anyway and I had to remove it to support the inline editing capabilities of JIRA 5.1.