PHP can be inconsistent

PHP can be inconsistent. Good PHP-programmers know its wayward temper. It is the payment for the seeming simplicity at the beginning. A naive beginner can be captivated by the absence of restraints. But experienced programmers know that the absolute liberty can cause a chaos.

In honor of Halloween some blogs published interesting scary examples of the PHP behavior. I liked this one and want to share:

Spooky Scary PHP

Let's read and remember: there is no perfection in our world and so let's use our sense of humor not to conclude bad things about the language. PHP has also the good features that make it one of the most used programming languages.

How to find files in a directory hierarchy that contain a string in Ubuntu

find . | grep 'string'

Search for files that contain string "string".

How to get the url of the current repository

git config --get remote.origin.url

How to get a form name from the twig-template in Symfony2?

It's pretty easy.

{{ form.vars.name }}

Relational Algebra Operations

How important is it to understand the relational algebra?

In the first place, the relational algebra is a part of computer science and so it should be useful thing ;)

Secondly, although the relational algebra is a formal model, it's the basis for database query languages. Widely used SQL is based on it. The study of the relational algebra is supposed to make the comprehension of SQL easier.

Foundations

First of all the relational algebra is a procedural query language. The word "procedural" means that the language consists of operations. The operations are performed on relations (tables or parts of them).

Relational Algebra Operations: