Aggregate vs Composite

I’m trying to wrap my head around the whole xPDO-concept.
Right now I’d like to know exactly what the difference between aggregate and composite relations are.

The only difference I’ve been able to find (by reading the code), is that when you delete an object, it’s composite relations will be deleted, but it’s aggregate relations will not. So essentially composite means "This related object does not make sense when current object is deleted".

Are there any other differences?

Is aggregate/composite a common term to use for such relations, and if so, what could I have read to know more about it?

Maybe check out OpenGeek’s response to a similar question of mine, here
http://modxcms.com/forums/index.php/topic,17980.0.html

Googling for "object relational mapping composite aggregate" turns up enough to show that it’s standard terminology.

There’s a lot of great information at this site as well:
http://www.agiledata.org/essays/mappingObjects.html

There are some object-relational strategies that I have not tried out yet in xPDO, but am hoping to.

Thank you! Just what I needed