Geek asks and answers

Why should I abstract from the data layer?

The principles of OOP were difficult for me because for some reason I could never apply them to web development. As I developed more and more projects, I began to understand how some parts of my code can use certain design patterns to make them easier to read, reuse, and maintain, so I started using it more and more.

The only thing I still can not understand is why I should abstract my data layer. Basically, if I need to print a list of elements stored in my database into a browser, I do something like:

$sql = 'SELECT * FROM table WHERE type = "type1"';'
$result = mysql_query($sql);

while($row = mysql_fetch_assoc($result))
{
    echo '<li>'.$row['name'].'</li>';
}

I read all of these How-Tos or articles preaching about the greatness of PDO, but I don’t understand why. I don’t seem to save LoCs, and I don’t see how it will be used more than once, because all the functions that I call above just seem to be encapsulated in the class, but they do the same. The only advantage that I see in PDO is prepared statements.

I am not saying that data abstraction is bad, I ask these questions because I am trying to develop my current classes correctly and they need to connect to the database, so I decided that I would do it the right way. Maybe I'm just reading bad articles on this topic :)

I would really appreciate any advice, links or concrete real-life examples on this subject!

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5 answers

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// Home page
$articles = $db->getTable('Article')->join('Author a')
    ->addSelect('a.name AS author_name');
$first_article_tags = $articles[0]->getRelated('Tag');

// Author profile
$articles = $db->getTable('Article')->join('Author a')
    ->addSelect('a.name AS author_name')->where('a.id = ?', $_GET['id']);

// Tag search results
$articles = $db->getTable('Article')->join('Author a')
    ->addSelect('a.name AS author_name')
    ->join('Tag')->where('Tag.slug = ?', $_GET['slug']);

, :

// Home page
$articles = Author::getArticles();
$first_article_tags = $articles[0]->getRelated('Tag');

// Author profile
$articles = Author::getArticles()->where('a.id = ?', $_GET['id']);

// Tag search results
$articles = Author::getArticles()
    ->join('Tag')->where('Tag.slug = ?', $_GET['slug']);

There are other good reasons for abstraction more or less, with its pluses and minuses. But, in my opinion, for most web projects, this is the main one: P

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