You may have been using relational databases in your PHP applications for a long time (PHP loves MySQL after all) but you might not have ever dug deep enough to understand how those databases work internally. In this detailed tutorial from Coding Geek they dive way in and cover everything from the basics out to complex sorting, management components and query handling.

When it comes to relational databases, I can’t help thinking that something is missing. They’re used everywhere. [...] you can google by yourself “how does a relational database work” to see how few results there are. [...] Are relational databases too old and too boring to be explained outside of university courses, research papers and books?

As a developer, I HATE using something I don’t understand. And, if databases have been used for 40 years, there must be a reason. [...] Over the years, I’ve spent hundreds of hours to really understand these weird black boxes I use every day. Relational Databases are very interesting because they’re based on useful and reusable concepts. If understanding a database interests you but you’ve never had the time or the will to dig into this wide subject, you should like this article.

He covers a wide range of topics during the post:

• O(1)) vs O(n2) (or how data sets are handled based on size)
• Array, Tree and Hash table
• Global overview (structure of the database system and its pieces)
• Query manager
• Statistics (and optimizing storage of the data)
• Data manager
• Deadlock
• Logging

Each of these topics comes with a lot of explanation, examples of how the internals are functioning as well as diagrams to help make a bit more sense. If you've ever really wanted to know how that database you use functions, this is definitely the article to check out.

In his latest post Michael Dowling looks at a recently proposed PSR standard (the HTTP message one, created by him) and some of his thoughts around it and what it could do for the community.

There's been a lot of talk lately about the PSR HTTP message proposal, PSR-7. The purpose of the proposal is to create a shared interface that can be used by projects to interact with HTTP messages for both clients and servers. When I created the proposal, I envisioned the purpose is not to say projects that utilize HTTP messages need to make breaking changes to use the proposed interfaces, but rather give projects an interface for which they can create an adapter.

He points out that the major part of the proposal that's being debated is the message body methods and structure. He gives a quick overview of this API and how streams could fit in with it, providing a flexible abstraction layer over the actual data. He includes a few ideas for some functionality that could make streams work relatively easily with the proposal (using a StreamInterface):

• No Auto-registering of stream protocols and filters
• Exceptions cause warnings in stream wrappers and filters
• Functionality is spread over many functions

He also shares an example (based around the Guzzle HTTP library) showing how this interface could be put to work. He also talks some about one of the major concerns voiced right now, getting the actual stream itself to work with, and shows how the "detach" method matches this goal.

In this new post to the Web Mozarts site, Bernhard talks about the architecture behind the current Symfony2 forms implementation and how it handles the requests your forms make.

Symfony2 features a brand-new Form component that, to my knowledge, supersedes most existing PHP form libraries in functionality and extensibility (not counting the still lacking, native JavaScript support). [...] The purpose of this post is to demonstrate that the Symfony2 Form component is perfectly suited for this requirement. Symfony2-specific functionality can be unplugged, leaving only the raw core dealing with form processing and abstraction.

The post is broken up into several different sections, each detailing a different aspect of this Forms functionality:

• It's influences from other frameworks
• Key aspects it provides
• Abstraction (reusable code)
• Extensibility
• Compositionality
• Separation of Concerns
• Model Binding
• Dynamic Behavior

Both a high-level architecture and low-level architecture are provided, showing you the internal flow behind the form handling. You can find out more about this component in the Symfony manual or peek into the code on github.