17. Summary

A database is a collection of data or information which is held together in an organised or logical way.    

Many databases are computerised.    

Databases store data or information in tables    

Each table consists of a number of records    

Each record is made up of a number of fields    

Every record has an unique identifier called the primary key    

Validation tries to make sure entered data is sensible, reasonable and allowable  

Verification means checking the data more than once e.g. typing a new password twice to make sure no typing mistakes have been made.    

A flat file database only consists of one table    

A relational database consists of a number of tables each with a relationship with at least one other table    

A table in a relational database is linked to other tables by making use of their primary keys.    

A query is used to extract data from a database    

Comparison Operators and Logical Operators are used to set up a query    

Reports present the results of a query in a neat, well laid out format.