This entry will focus on our use of the database, and specifically on the already_tweeted() method. This method has a number of problems, and while we're focusing on the implementation of the database, it's important to note that we will also need to address some of the logic (which will be the next part of the series).

He looks at assumptions (how they can be bad), the use of an ORM layer to help negate some of the problems surrounding them and adding in some exceptions to properly handle issues that might come up.

In my opinion, the most annoying and worst for cleaning up the system are the functions/methods that make too many assumptions for you. It could be a variety of things - assuming a database connection, assuming what the output destination is, or assuming what the input is - but I most often see it in scrubbing/cleaning functions.

His example is a function that not only assumes that the type of input is correct but also returns the value via an echo rather than a return (despite the name of the function implying the second). As a follow-up, he also suggests that libraries/external tools don't make assumptions when it comes to stopping execution of the script either.