Object identity refers to the unique identification assigned to an object in an object-oriented data model. In this context, every object is given a special identifier known as an object ID, which is used to distinguish it from other objects. This ID is crucial for establishing connections between objects and facilitates the retrieval and comparison of data based on these internal identifiers rather than relying on the attribute values of an object.
In object-oriented (OO) programming languages, mechanisms for object identification are typically built into the language itself, eliminating the need for explicit creation of object identifier types. For instance, in C++, an object’s actual memory address functions as a unique identifier. You can obtain this address by using the ‘&’ operator with an object or object reference.
To test object identity, one can perform pointer comparison. In simpler terms, you compare the memory addresses of two objects. If the addresses match, it means the objects are the same. This approach is more direct and efficient than comparing the values of attributes, as it directly assesses whether two references point to the exact same object in memory.