Asp.net project dependency issue (Building each tier separately)

Question

Project1 = Asp.net pages project (presentation Layer)

Project2 = Data Access Layer

when Project1 is hosted and running smooth, if i have to add few PRIVATE metho

Answer 1

First of all separate tier doesn't really mean separate assemblies. A multitier archtecture program can easily be stored in 1 assembly and have DAL, presentation and BL classes separated by some logical separator like namespace or even project folders with classes (or even no logical separation whatsoever, but you will known that certain set of classes is for DAl, and annother for BL, etc)

To your question - if your DAL is generic and has a fixed interface you can update your dal assembly ( for example fix some buggy methods, or something else) if you dont change interface of public methods. Obviously if you change some interface your other assemblies that reference this assembly will have to be not only rebuild but rewritten in order to use new method names for example

Answer 2

You don't HAVE to rebuild it. You can just copy the new project2 dll to the web app\bin directory and it will work if the interface hasn't changed. A build of project1 will redundantly rebuild project1 and produce the same result, and also include the latest version of project2, that's why it works, too.