As you already know a textbook three tier application would be web based…
HTML/Javascript/CSS - Front End PHP/JS/ASP… many others - Middleware MySQL, Oracle etc - Backend The key points being: Front end handles the presentation Middle ware handles the business logic and application flow talks between the front end and any other resources needed Backend a connection to permanent data usually through SQL There is no reason that 4D couldn’t be used in all three, but it really doesn’t make sense… Front End - 4D handling the presentation with screens (but no database nor tables) making calls to the middle layer… and accepting data and navigation from the middle layer (via REST or some other communication) Middleware - Use 4D code to handle requests from the front end, validate data, handle the controller part (again no database nor tables)… make calls the backend (REST etc. or using v18 ORDA to make direct queries) Backend - Use 4D structure with data but no code (expose with REST or ORDA) A couple of possibilities maximizing 4D use: Web Browser -> 4D middleware server -> 4D backend Web Browser -> 4D Client -> 4D Server Anyway in short I don’t know of a way to go three tier without a lot of work. And for a true 3 tier, web is a good way to do it. Neil > On Jan 27, 2020, at 8:48 PM, Tarawerkz via 4D_Tech <[email protected]> > wrote: > > Hi All, > > I have an application running in a hospital environment for a number of years. > In the light of the increasing awareness of data security, the client’s IT in > their own words are looking at "redoing the whole 4dcis database onto 2 or 3 > tier system where there is a database separation from application layer” > > The current setup is a v15 client-server application, with about 80 > concurrent client licenses serving users located at 2 separate locations. > > As it stands, a 4D application already has a 2-layer architecture being a > client-server application. > We could perhaps enhance it a little to make it a 2-tier environment by > moving the segregating the 4D Server software and the 4D structure files > (business logic) on to one server and the 4D data files (database) on to a > separate server. Doing that however has no effect on the 4D database > architecture, it still remains a 2-layer database architecture. > > Apart from re-developing the application into a complete web-based > application, how can a 4D application be refreshed into a 3-tier system? > > I would like to tap on the collective wisdom of the forum to gather some > views on the plausibility of the above. > Thank you. > > Regards, > Ronnie > Tarawerkz > > > > > ********************************************************************** > 4D Internet Users Group (4D iNUG) > Archive: http://lists.4d.com/archives.html > Options: https://lists.4d.com/mailman/options/4d_tech > Unsub: mailto:[email protected] > ********************************************************************** ********************************************************************** 4D Internet Users Group (4D iNUG) Archive: http://lists.4d.com/archives.html Options: https://lists.4d.com/mailman/options/4d_tech Unsub: mailto:[email protected] **********************************************************************
