Object graph: Difference between revisions

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An '''Object Graphgraph''' is a view of an object system at a particular point in time. Whereas a normal [[data model]] such as an [[Uml]] [[Class diagram]] details the relationships between objects, the object graph relates thetheir instances. [[Object diagram|Object diagrams]] are subset of the overall object graph.

Object graph is a term often used with object-oriented applications. Object-oriented applications contain complex webs of interrelated objects. Objects are linked to each other by one object either owning or containing another object or holding a reference to another object. This web of objects is called an object graph and it is the more abstract structure that can be used in discussing an application's state.

==Physical representation==

e.g. Instead of a car having a relationship to a wheel, MyCar has four relationships to four different Wheels (FrontLeft, FrontRight, BackLeft, BackRight).

An object graph it's a [[directed graph]], which might be [[Cycle graph|cyclic]]. When stored in [[Random access memory|Ram]], objects occupy different segments of the memory with their attributes and function table, while relationships are represented by [[Pointer_(computing)|pointers]] or a different type of global handlers in higher-level languages.

==Examples==

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For instance, a Car class can compose a Wheel one. In the object graph a Car instance will have up to four links to its wheels, which can be named frontLeft, frontRight, backLeft and backRight.

Object graph is a term often used with object-oriented applications. Object-oriented applications contain complex webs of interrelated objects. Objects are linked to each other by one object either owning or containing another object or holding a reference to another object. This web of objects is called an object graph.

Example of an [[adjacency list]] representation: c:Car → {frontLeft:Wheel, frontRight:Wheel, backLeft:Wheel, backRight:Wheel}.

Example: A → {B, C}, B → {D}, C → {A, D}, D → {B, A}.

==See also==

* [[Data model]]

* [[Object diagram]]

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