database implementer builds the database system. The
database designer establishes the schema for a database and therefore figures out how the structure the data so that application can be build around those schemas. The
Database Application Developer builds the Applications or programs that are going to run on the database, often interfering between eventual users and the data itself. Thus, s/he makes the programs that operate on the database. It is common to have a database with many different program operating on it. The
database administrator is the one who loads the data, sort of get the whole thing running and keeps it running smoothly. It is a very important role for large database Applications. Database systems to tend to have a number of tuning parameters associated with them. Getting those parameters right can make a significant difference in the all important performance of the database system.