Especially when working with ADF Business Components you may only a single Data Control being used when working within an application. Because the ADF Business Components Data Control is used a lot in written collateral, guided how-to and samples, as well as video recordings, it neglects the fact that you can of course work with multiple Data Controls in an ADF application.
There is no restriction other than developer wisdom in the number of Data Controls to use within a project. Data Controls can also be of different types and, if needed be used to pass data from one business service to another based on user interaction. If you need to look up and access a Data Control from Java, you can do so by calling BindingContext.getCurrent() to obtain a handle to the runtime object that represents the DataBindings.cpx design time file. On the binding context you then call findDataControl(String)to access the data control, where the "String" argument is the ID the data control has in the DataBinings.cpx configuration.
When creating new bindings declaratively in the PageDef file of a page or a view, you can select from a list of available Data Controls defined in the DataBinings.cpx file.
Note however, that not all Data Controls need to be defined in the DataBinings.cpx file, as they can also be imported as part of an ADF Library.