If you are downloading the EA1 of SQL Developer that includes Oracle Data Miner (ODMr), and you intend to use Oracle Data Miner then you will need to update the ODMr Repository.
You could do it the hard way and run the upgrade repository sql scripts that are located in the ...\sqldeveloper-18.104.22.168.29-no-jre\sqldeveloper\dataminer\scripts directory.
Or you could do it the easy way and let the inbuilt functionality in Oracle Data Miner do it for you.
To do it the easy way all you need to do is to open the ODMr Connections window and the double click on one of your ODM connections.
ODMr will check the version of the repository you have installed and if needed it will prompt you about upgrading the repository. Select Yes and you will be prompted to enter the SYS password. So talk kindly with your DBA for them to enter the password for you. Then click on the Start button. They will lick off the OMDr Repository Upgrade scripts.
NB: Make sure you have a backup of your workflows before you do this. A little think happened to me during the SQL Dev / ODMr 4.0 upgrade back in September 2013 where all my workflows disappeared. You can imagine how happy I was about that. Since then the ODMr team have added some functionality to ensure something like this doesn't happen again. But you never know.
To backup your ODMr workflows use the Export Workflow option.
When the repository upgrade has finished you will get a 'Task Complete Successfully' message in the upgrade window. Click on the close button and away you go with this updated version.