Core PHP Programming, Third Edition

6.1. Object-Oriented Programming

Object-oriented programming was devised as a solution to problems associated with large software projects where many programmers work on a single system. When source code grows to be tens of thousands of lines of code or more, each change can cause unexpected side effects. This happens when modules form secret alliances, as nations did in pre-WWI Europe. Imagine a module for handling logins that allows a credit card processing module to share its database connection. Surely it was done with the best intentions, probably to save the overhead of acquiring another connection. Some time later, the login module severs the agreement by changing the variable name. The credit card processing code breaks; then the module ...