Here is how you can find one:
In the View menu select the Data View Window. This will display a window with a tree structure, (Data Links being the root.)
right click on the data links root item and select Add a data link.
This will display the Data Link Properties window.
Choose the oracle driver you are looking for (I perfer the one from oracle over the one from Microsoft).
Click the next button. This will take you to the connection tab.
Enter the appropriate information, and click test connection.
Now in the Data View window, right click on the new entry (probably DataLink1) and choose properties. Your connection string will appear in the Name Property.
You can use this as a base, and edit it as need be.
John R Lick