From the Autonomous Tools tab, when we click on “Open Database Actions” -
we are forwarded to a page to enter a username -
then to a second page to enter a username and password -
Why am I being prompted twice?
The first prompt is for your schema as it is known by ORDS. When you REST enable a database account, you have the option of providing an ALIAS, such that RESTful Web Services and their associated URIs don't have your database username in the addresses.
So I could create a schema called FOO, but alias it to FOOBAR.
To login to my SQL worksheet in Database Actions, I would enter FOOBAR in the first box.
ORDS then sees that schema mapping is available and sets the URL correctly, and brings you to the database login page.
On the second prompt, you enter your actual username and password - this is used to attempt a login to the database. If that succeeds, you get to use Database Actions (formerly known as SQL Developer Web).
If you're always using the same user on the same db, you can simply bookmark the URL, and then go directly to your SQL worksheet or REST workshop or or or - and since the right schema alias is in the URL, we'll know exactly who you need to login as, so only the single login prompt.