14. Database Queries

Databases are extremely good at storing data or information. However, they are only any use if we can find specific information from them.

Searching the database to find specific information is known as a query.

If we wanted to search our Vet's database to find all of the dogs he looks after, we would set up a query and choose the criteria 'dog' as shown below:

We would then 'run' the query and the database would search for all of the records which matched the criteria 'dog'. We would get the following results:

Queries can be used to search for more than one thing, for example, we could search for all of the dogs who don't have any medical conditions:

And we would get the following results:

You can also search for specific things like 'all of the dogs born before 2000' or all of the pets who have had an appointment between 01/01/05 AND 31/12/05.