When I read your questions, I think you are asking how to restrict the connection to the database to read only.
There are two ways, basically.
First, you can use the same user you have set up now. While the user permissions are full, you may change the ODBC connection string to restrict to READ ONLY.
If you use the QlikView wizard to connect via ODBC, that will give you the basic connection string, modify as you like to restrict to read only.
Second, you could create a new database user which is read-only and specific to the application, in this case QlikView. After you do that, use those new credentials to read data into QlikView.
The second way is standard practice in most organizations, because it gives the DBAs good information about which machine/process is accessing data, when and how.
Hope that helps.