SqlSpec is from Elsasoft. It works well for SQL Server, better than SQL Doc, SQL Document Tool according to my evaluation.
However, you may not see information you are interested in Oracle, but still good in the schema level.
Here is the link. You can download an evaluation version for your trial.
just $149 for a single user, I think it is pretty worth.
Examples of Connection String:
For SQL Server
server="serverName\instanceName"; database=dbName; user id=userName; pwd=yourPassword
Provider=OraOLEDB.Oracle;Data Source=tnsName;User Id=userName;Password=yourPassword