[ QUOTE ]
How can we connect to DB by manual scripting?
ie.in the sacript i want to take each username and password from the DB.
[/ QUOTE ]
This can't be done directly in OpenSTA. If you have a db full of usernames/passwords, you could export them to text files which OpenSTA can then read and dynamically use in your scripts. However, you can not query a database from your OpenSTA script.
You can also use OpenSTA to get them from the DB and put them in text files for you. May be limited to MS Access DB. From the modeler go to Variable>Create then change the source to database and follow the instructions.
But, yep as Corey says, when running, OpenSTA can only get the values from text files or values defined in the script iself, not the database.