In the early 1990's, Microneering designed and installed production systems with three tiers.




Needless to say, at that time shop floor never got computers ( that was for email and managers only). This installation supported both Electronic Work Instructions and collection of many shop floor data points, such as hours worked, etc. And a database for the production area was unthinkable.

The data layer was soon further separated in to database middle ware (DPlan) and the database, creating our current 5-tier cloud systems. This made the application layers database independent.

Now any database can sit under our applications, and there is no need to reprogram for each specific database. Database logic can reside as SQL in DPLAN, but most DPlan simply delegated to the database as "exec myStoredProcedure(?);".

This method of parameterization of arguments prevented security holes like SQL injection.