databases

databases

1. A database is a way of storing information in an organised, logical way. It's important to know when to use a database and be aware of its advantages.

2. Microsoft access is an example of a database

   • organised data
   • Computer has validation, can be backed up, can be shared and uses up less storage
   • One table is a flat file, Multiple tables is a relational table
   • Queries allow you to search of a field of data

3. Entity

   • the thing that the table is for
   • Different entities can be linked together
     • the primary key links them
     • relationships
       • one - one
       • many - many
       • one - many

4. queiry

   • the use of the table is to answer quries
   • “and” takes preference over “or”
   • brings up the data for the criteria

5. data seperation

   • A DBMS allows the separation of data
     • database management system
     • a persistent organised store of data
   • data held in various entities is held separate from the applications that use it
   • Different people have different levels of access

6. reports

   • Reports are based on queries
   • The report always uses the most up to date data so it is never out of date