Databases

Databases

1. What is a database?

   • A database is a collection of information that is organized so that it can easily be accessed, managed, and updated

2. What are databases manipulated with?

   • Most databases are manipulated with a Database Management System (DBMS).
     • A DBMS provides the software tools to create, maintain and interrogate a database
     • The physical data is handled by the DBMS.
     • The database programmer writes applications software that works through the DBMS.

3. What must the DBMS do?

   • allow data sharing
   • allow multiple user access
   • allow multiple applications to work on them
   • hold just one copy of data that everyone can access – this prevents inconsistent updates
   • make it possible to change the data in a database without having to change the applications
   • provide multiple views
   • present data to different users in different ways
     • The human resources department needs full personal details of employees
     • A co-worker might just need to see a colleague’s telephone number
   • The DBMS must protect data from inconsistent requirements