If I need to display data from a customized database to a webpart for a SP solution 2013, what approach or tool is the recommended or best practice to do it? What is the common approach to use it to faciliate the work? I'm talking about Nhibernate, bindlinglist, Entity Framework etc.
What we did was deploy our Business-Logic and Data-Access Layers to the GAC as a dll, and in our SharePoint WebParts, we referenced these dlls. Whenever I need to call upon a service in my BLL, create an instance of a model, query the custom DB (we only use Stored Procedures) etc., we just had to include the proper reference in the class. Moreover, if I ever had to update the layers to add a new service/model/entity it would be a single update.