在一个表或多个表中管理不同类别？

Question

I am making an article website. I have a database called CATEGORIES with tables: Articles , Entertainment , Lifestyle . Articles contains all the entries of both Entertainment and Lifestyle . Entertainment contains all entries of Entertainment type and Lifestyle contains all entries of Lifestyle type. Each table has 7 columns: id, category (category of the article), link (link of the article), title (title of the article), image (image URL of the article), Counter (the number of views of the article), dateStamp (the date in which the article was written).

Would it be more efficient to get rid of the Lifestyle and Entertainment tables, and just rely on the Articles table? The reason why I separated them this way is because when the user is reading let's say an Entertainment article, a random list of Entertainment articles are shown. To show random articles I take the highest id in the Entertainment table, get a random number between 6 and the highest id (6 is the number of articles I want to display), and then let's say I get 8 off of the random generator, then articles 8 though 3 are displayed ( DESC LIMIT 6 ). Here's the code:

<?php

$MAX_ID = $db->query("SELECT MAX(id) FROM Entertainment");
$MAX_ID = $MAX_ID->fetch_array();
$MAX_ID = $MAX_ID[0];

$RAND_NUM = mt_rand(6, $MAX_ID);

$resultSet = $db->query("SELECT * FROM Entertainment 
                             WHERE id <= $RAND_NUM ORDER BY id DESC LIMIT 6");

if ($resultSet->num_rows != 0) {
    $conditional = true;
    $conditional2 = true;
    echo "<div class='row'>";
    while ($rows = $resultSet->fetch_assoc()) {
        $image = $rows["image"];
        $title = $rows["title"];
        $link = $rows["link"];
        $count = number_format($rows["Counter"]);

        if ($conditional == true && $conditional2 == true) {
            // display articles
        } else {
            // display other articles
        }
    }
}

If I removed the Entertainment table, then this query would not work, and I don't know how else I would make it. The final question is would it be more efficient (performance wise) to separate the tables into different categories or combine the tables into one table?

Answer 1

Never make one table per widget.

If two tables have virtually identical columns, then they probably should be combined into a single table. It may need an extra column to tell the things apart. And changes to the indexes.

Normalize, but don't over-normalize. Do not, for example normalize 'continuous' values like DATETIME or FLOAT.

Do have a PRIMARY KEY on every table. Consider using a "natural" PK, or use an AUTO_INCREMENT. (Sometimes one is the obvious choice; sometimes the other; and sometimes it is a coin-flip.)

Your code snippet smells like you want some 'random' rows. My blog on such.