On 5/3/2015 1:45 AM, Dimitre Novatchev wrote:
> ...
> Now, notice that the book object representing "The Giver" by Lois Lowry,
> takes part in both collections. This is another example how two
> different JSON objects share a single third JSON object.
>
> One could argue that these are two different JSON objects that happen to
> represent the same book. This is not true, because these "two objects"
> cannot have their own different data and if we want to change, for
> example, the year when the book was written, we must make the change in
> both of these "two objects".
Well, actually, there is nothing to indicate that these two objects are
the same. A javascript engine would create two objects, and if you were
to change the properties of one, the other's properties would not
automatically change.
A graph is a set of nodes and edges. Each edge is labeled with the two
nodes that is connects (well, there could be a separate record of these
connections, but this is one way). So a simple JSON graph could be
given by (omitting quotations marks from the labels "edge" and "node"
for simplicity):
{graph:
{node: "N1"}, {node: "N2"}, {node: "N3"},
{edge: {from: "N1", to: "N2"}},
{edge: {from: "N2", to: "N3"}},
{edge: {from: "N1", to: "N3"}}
}
You could also use edge:["N1", "N2"], ..., but the first way lets you
add other named properties to an edge.
You could augment the properties of each node or edge as you like, of
course. It's true that nothing in the JSON shows (by the construction
of the objects) that the nodes have any relation to the edges. Your
code has to provide that interpretation. That's because JSON does not
provide a notion of object identity, just objects and lists. But this
lack comes from the simplicity.
