php singleton database connection, is this code bad practice?

Question

I\'m trying to create a simple to use singleton class to connect to mysql database and do queries, the code works fine and i haven\'t had any problems with it, but since I\'

Answer 1

Singletons are bad news.

• They introduce global state into a program. Most programmers should be familiar with why global state is bad.
• They introduce tight coupling between the singleton and any class that uses it. This means you can't reuse the classes in question without reusing the singleton too.
• They make unit testing of classes that depend on the singleton problematic because you can't easily replace the singleton with a mock.
• They encourage a coding style where classes attempt to resolve their own dependencies. This is bad because it can reduce clarity regarding what dependencies the class has.
• PHP has a Share Nothing Architecture, meaning that PHP singletons aren't really singletons at all, there can be multiple instances alive at any one time (one per open request).
• What happens if you suddenly discover at some later date that you actually need more than one of the resource that's being provided by the singleton? It's a more common scenario than you might think

You're better off looking at dependency-injection instead, as it resolves the above issues.