You cannot delete a database directly from InfoWorks WS Pro. This reduces the chance of databases being lost accidentally.
However, administrators have the option of deleting a large amount of data (see Bulk deleting data).
If you want to delete a transportable database you must use the standard Windows procedures.
You should use the tools supplied with SQL Server to delete a database. Speak to the administrator of your SQL Server database.
You will have to use the tools supplied with Oracle to delete a database. Speak to the administrator of your Oracle database server.