1. Swiss Federal Institute of Technology 1 Models for DB Connectivity n simple HTML for client, adjustable complexity for middleware limited SW power logic hierarchically distributed simplest SW distribution (none) transient connection (data transfer) stateless model no client-side transaction support 2-tier architecture3-tier architecture Browser DBMS Browser Web Server complicated programming great SW power logic client-sided complicated SW distribution permanent connection with client sided transaction support Connectivity: 2/3 Tier

2. Swiss Federal Institute of Technology 2 Models for DB Connectivity n CGI DBMS Browser Web Server DLL ASP Connectivity: CGI, DLL, ASP

3. Swiss Federal Institute of Technology 3 Models for DB Connectivity n Common Gatway Interface independent programs in separate processes PERL, REXX, or any prog. language CGI DLL ASP proprietary: ISAPI, NSAPI efficient, same process as server any prog. Language comfortable development environment (FP, Livewire) may perjudice server process Proprietary (see also ColdFusion) efficient, same process as server scripts (VB, JS), JApplets, ActiveX controls comfortable development environment (Visual IDev) Connectivity: CGI, DLL, ASP Details