Basic concepts

Computers store data. Data can be any one of several different types (e.g. numeric, text, Boolean etc.) but has no intrinsic meaning to a human. Data becomes information when it is put into a context that gives it meaning.

For example: 32 23 11 08 40 17 is data, but it has no meaning.

If we provide a context for that data, it becomes information, e.g.:

• The home and away scores for 6 soccer teams last Saturday
• The temperatures in degrees Celsius for 6 cities around the world at mid-day today
• The ages in years of the last 6 people to walk through the turnstiles of the Eiffel Tower in Paris.

Thus: Information = Data + context

ACID refers to:

• atomicity
• consistency
• isolation
• durability.

Query functions and update functions