|Tutorial: (Objects) Simple Accounting System; Version 0.0.1; Document Revision $Revision: 1.17 $|
|Prev||Chapter 1. Overview||Next|
Ada 95 provides no means to relate objects to each other except access types. The disadvantage of using pointer are:
Pointers can not be stored in a database
It is easy to go from A to B but it is not possible to find out what objects are referencing B.
Relation between the instances A and B in Objects are expressed by three values:
Source object id
Target object id
A relation name
Lets assume there is a person instance. This instance may be associated with upto N account instances. This may be expressed by the relation name Has_Account where the source the account is and the target the person instance.