04 Try it yourself Interactive

Send the same request through both designs

The same student, the same query from section 02, in two runs. 2-tier connects the laptop straight to the database. 3-tier puts an application server in between. Each run does the single request first, then results day, when 200 students arrive at once. Watch two things in particular: the chip showing which machine holds the database login, and the connection meter under the diagram. Every press of Next moves the diagram, the meter, the highlighted plan line and the narration together.

2-tier
install · the login ships with the app
Indigo = the machine doing the work this step. Rose = something refused or unsafe. Green = a connection or a fact that is safely in one place.
Database connectionsnone yet
Press Next to start the run.
Press Next to begin. Each press advances the request by one step.


      

        
Round trips–

        
DB connections–

        
Students served0

        
Students refused0

      


      

      

        
        
        
        step 0 / 0