intro

Why do we need a DBMS (Database Management System)?

• Store huge amount of data (e.g., TB+) over a long period of time
• Allow apps to query and update data
  • Query: what is Mary’s grade in the “Operating System” course?
  • Update: enroll Mary in the “Database” course
• Protect from unauthorized access.
  • Students cannot change their course grades.
• Protect from system crashes
  • When some system components fail (hard drive, network, etc.), database can be restored to a good state.

More on what can DBMS do for applications?

• Protect from incorrect inputs
  • Mary has registered for 100 courses
• Support concurrent access from multiple users
  • 1000 students using the registration system at the same time
• Allow administrators to easily change data
  • schema
    • At a later time, add TA info to courses.
• Efficient database operations
  • Search for students with 5 highest GPAs