The Database Repository must be connected to your database to retrieve schema information. A Datastore is added to manage the connection and hold the schema information.
method 1
Click on the Execute link in the Action Balloon that appears:
method 2
If the Action Balloon has disappeared (if you clicked the Close link or if you switched applications), you can double click the task in the Actions Pane. If the Actions pane is not showing on the screen you can open it by clicking the Actions button 
on the Standard Toolbar.
Now a tabbed window titled DataStore1 appears with the Provider tab active. Here you can specify your database connection. Start by selecting the type of database that you're connecting to.
Fill out the details of your connection (these change according to the type of database selected), then click on the Connect button.
