I have an assignment to do with databases at college and there is one part where it says something about "data structure". How do I write about that? I have already completed the database if that helps. What kind of things do I write about concerning the data structure?

Thank you in advance.

Andy.

Think about the following data structures:

• An ordered list
• key-value pairs
• A hierarchy (e.g., an XML document)
• An undirected graph
• A directed graph
• A labeled, directed multigraph (e.g., a set of RDF Triples)

You don’t have to think very hard to see that any of these can be viewed as a restricted version of the data structures above it. An ordered list (array) is just a set of key-value pairs where the keys represent each item’s sequence. A set of key-value pairs is a very, very flat hierarchy. A hierarchy is an undirected graph without cycles. An undirected graph is a directed graph where you’re careful to make links both ways. And a directed graph can easily be represented as a set of RDF triples (where you may, for example, only have one label for your relationships: “links to”).The structures at the end of the list have more expressiveness. You can just plain model more things in them (give-or-take the out-of-band stuff, composition, etc) per unit of screwing around. I’m not going to try to model my set of key=value pairs in an array. I could do it, but it would take so much of my attention that the data modeling would suffer.

I never had a class on the subject but I think that the "data structure" for a database would be a detailed explanation of the fields and organization of the DB including indexes.

I am sure Chris or someone better educated will be along later today.