Database Revision

Database Revision

1. What is the database?

   • A database is a system designed to store data in an organised way.
   • It needs to be reliable, consistent and persistent
     • Persistent means that the structure is fixed in place.

2. Computerised databases

   • Can store huge amounts of data
   • Can update automatically.
   • If you have the right security set up it's very hard for other people to access.

3. Paper based databases

   • Can not store huge amounts of data.
   • You have to update the database manually.
   • Easy to access iso not good for security

4. Types of databases.

   • Flat File
     • Only one table
     • Primary key which uniquely indentifies records.
     • Simple Tables
   • Relational
     • Can have more than one table
     • Foreign key which links the tables together
     • Used for more complicated subjects

5. Types of a database

   • Field-
   • Attribute
   • Entity
   • Table