What is a relation anyway?
Short story: A relation is a set of tuples that share the same properties. Each tuple is unique.
|Die göttliche Ordnung||FIC||357'413|
|More Than Honey||DOC||256'195|
|Ma vie de Courgette||ANI||179'328|
A relation can be represented in a tabular form.
Each row is a tuple. Each column is a property.
Each property represents a domain. Titles are text, genre one of FIC, DOC, ANI, admission numbers.
With the Relation language, we keep it simple: All values are of the domain text of any length. However, they can behave like numbers if the context needs it.
Having this relation, we can now start questions.
What is total number of admissions?
What is the share of admissions by genre?
Now let's have another relation.
|Die göttliche Ordnung||Filmcoopi|
|Ma vie de Courgette||Praesens|
|More Than Honey||Frenetic|
We can now ask questions on both relations, based on their common poperty title.
How many films and admissions got each distributor?
This is more or less all we do with relations. We filter, combine, aggregate to get consise information.
What you read here, is itself the output of a Relation document. You program and you comment. And once you have done it, you could reuse the code with other data.