specify multiple <dbconnection> elements in the dbforms-config.xml

It is allowed to have at most 1 connection without an id within a config file. That will be the default connection.

Specify the dbConnectionName to be the id of the dbconnection you wish to use in relevant tags including: dbform, tableData, queryData, getConnection, blobContent

        <db:select fieldName="tc">         
        <db:queryData name ="combinations" query="SELECT DISTINCT tc, tier, course FROM coursesORDER BY tc"
    disableCache="true" 
        dbConnectionName="simple"/>
           
        </db:select>
      

would be used with a connection such as the following:

        <dbconnection
        id = "simple" 
    <<< this will be used for the connectionName (your arbitrary choice)
    isJndi = "false"
    isPow2 = "true" 
    connectionProviderClass = "org.dbforms.conprovider.SimpleConnectionProvider" 
    connectionPoolURL = "" 
    conClass = "org.postgresql.Driver" 
    name ="jdbc:postgresql://localhost/myDatabase?charSet=ISO-8859-1"
    username = "postgres" 
    password = ""
        />