A report can extract data from several different Datasets (tables). The Birt report writer uses the Data Tools Platform to create and manage database connections.

Connection Profile

You do not need to create a new connection profile and re-bind to your report designs every time your connection parameters change. Using a connection profile externalizes the connection properties, so their values can change (within the connection profile store file), and the associated report designs would see its latest values.

To change the connection property values in an exported connection profile, there are alternate ways to do it.
You can use the Data Source Explorer in Eclipse IDE, by first importing the profile(s) from your profile store file, edit the properties, and then re-export the latest profile(s) back to a profile store file. Then re-deploy the latest profile store file with the same file path and name to your environment.

You can find its documentation in the Help Contents from your IDE (assuming BIRT all-in-one package is installed).
From the IDE Help menu, select "Help Contents" to bring up the Help dialog.
http://127.0.0.1:51167/help/index.jsp

Look under "Data Tools Platform User Documentation" -> Creating a Connection Profile and other topics.