Spencer, I gotta tell you, I'm impressed.
You're getting very good at this. So, why
don't you go wild and continue, there
anything else you think we can improve here?
>> Well something was bothering
me, that what happens if there's more
than one book with the same title and somebody puts in a request?
>> Oh, I see. That's a good point. So basically what you are telling me is
there's kind of a difference between an item and
the title, so the title is kind of a more
general concept, in a sense. So if you can
have multiple copies of a given title, is that right?
>> Yeah, we have five copies of Tom Sawyer, and the
persons, the patrons, really putting in a request for any Tom Sawyer.
>> They don't want like copy number three of Tom Sawyer, right? They want,
they want to read Tom Sawyer. Okay and I can represent that. So, in which
I suggest we do that, and you can tell me whether it makes sense to you is by
introducing an additional class, which I call Title. And
that represents exactly the concept that you're mentioning. So
this is a title which represents some
specific content. That is not related to a specific
physical element. Like it can be rated to multiple,
physical elements. So basically I'm going to create this title.
And then I'm going to create a relationship between
the title and the item. And what
the relationship is telling me, the the association
between these two in this case. Is an association,
that we call aggregation. So it's a special kind of association, that basically
indicates that an item of this type, so a title can
consist of a multiple elements of this type of multiple items.
So it's telling me that one title can
consist of multiple items, and I'm going to indicate
it with this annotation, which is a this
diamond at the top of the association.
>> And so we can move our request
line, up from loanable item to
title, because that's what they're really requesting.
>> Definitely, definitely, and in fact,
you know, that represents exactly the situation
that you are mentioning, at this point when the patron makes a request.
It makes a request to a title and not to a loanable item. And then, and
when the actual loan will take place,
then that will be connected to a specific item.
>> Right. Okay that makes sense.
>> Makes sense?
>> Yeah.
>> Okay, good.