we must understand client requirements to start working in database this called system analysis.
DB design => transfer requirements to shape called ERD(Entity relationship diagram) , the one who do this called DB designer.
Entity is the object who i should store data about it inside the system.
for example: school=>(courses, students, teachers...etc.).
DB mapping => set of roles provides actual schema , Tables. who do this called DB designer.
DB implementation (physical DB): collection of tools=>RDBMS(SQL server ,oracle ,MySQL) => DB developer.
After downloading sql server ,your computer became DB server.
Any DB must be centralized and shared.
If you have two different DB on different servers this called inconsistent DB.
Application (GUI): interact with database.