Running queries
Databases can hold huge amounts of Values, typically letters or numbers.. Queries find specific data based on set A set of rules or conditions that must be met. Often used in searches..
Query scenario
A burglary has happened in a local village. The police create a query to search their database for suspects. The fields queried are:
- first name
- last name
- known for
The table queried is 鈥楥riminals鈥. The results return a list of first names and last names and the crimes each individual is known for. One man is known for burglary.
Narrowing down the results
The police add the field 鈥業n prison鈥 to the query and add search criteria so that it only returns people currently in prison. The man comes up as a result, so he cannot have committed the crime because the police know he was in prison.