What you are trying to do is called "slugify", which is to create a slug, as a unique identifier for a resource (the post in the case). A good example is the URL itself for your question here in Stackoverflow. stackoverflow.com/questions/59475/due-in-relation-to-link-persistent-for-posts - the slug as well as being a readable identifier for a resource, it is still completely SEO friendly. Google loves slugs.

Learn more about it: What is Slug? And the importance of friendly URLs on the Blog - ignore "in the Blog", this applies to any content.

Initial structure for slugs

Have a "slug" column in the posts table in your database. When the post is created, you generate the slug using the post title. As we will be creating a simple system of slugs, to avoid collisions it is recommended to attach the post ID or a unique identifier, which can be the user ID (and there is no security problem when placing the IDs).

For example:

• Title: How to create permanent links?
• Slug: how-create-links-permanent-120 (120 = post id in database)

How to redirect links to posts

If you have your application structured using MVC, you probably already bootstrap your application in just one file, probably index.php. In this case you need a rule for Apache (or nginx) to recognize the links and pass the slugs to your application:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

For a call like link , the path next to the slug will be available in $ _SERVER ['REQUEST_URI ']:

[REQUEST_URI] => /posts/como-criar-links-permanentes-120

However, if you are not structured in MVC, and use individual files for resources, for example: post.php, nothing prevents you from using query string as permanent links:

http://localhost/post.php?slug=como-criar-links-permanentes-120

So you just get the slug in $ _GET ['slug'].

Creating slugs

The possibilities are endless, but here are some examples of functions:

No external dependencies ( source ):

function url_slug($str, $options = array()) {
    // Make sure string is in UTF-8 and strip invalid UTF-8 characters
    $str = mb_convert_encoding((string)$str, 'UTF-8', mb_list_encodings());

    $defaults = array(
        'delimiter' => '-',
        'limit' => null,
        'lowercase' => true,
        'replacements' => array(),
        'transliterate' => false,
    );

    // Merge options
    $options = array_merge($defaults, $options);

    $char_map = array(
        // Latin
        'À' => 'A', 'Á' => 'A', 'Â' => 'A', 'Ã' => 'A', 'Ä' => 'A', 'Å' => 'A', 'Æ' => 'AE', 'Ç' => 'C',
        'È' => 'E', 'É' => 'E', 'Ê' => 'E', 'Ë' => 'E', 'Ì' => 'I', 'Í' => 'I', 'Î' => 'I', 'Ï' => 'I',
        'Ð' => 'D', 'Ñ' => 'N', 'Ò' => 'O', 'Ó' => 'O', 'Ô' => 'O', 'Õ' => 'O', 'Ö' => 'O', 'Ő' => 'O',
        'Ø' => 'O', 'Ù' => 'U', 'Ú' => 'U', 'Û' => 'U', 'Ü' => 'U', 'Ű' => 'U', 'Ý' => 'Y', 'Þ' => 'TH',
        'ß' => 'ss',
        'à' => 'a', 'á' => 'a', 'â' => 'a', 'ã' => 'a', 'ä' => 'a', 'å' => 'a', 'æ' => 'ae', 'ç' => 'c',
        'è' => 'e', 'é' => 'e', 'ê' => 'e', 'ë' => 'e', 'ì' => 'i', 'í' => 'i', 'î' => 'i', 'ï' => 'i',
        'ð' => 'd', 'ñ' => 'n', 'ò' => 'o', 'ó' => 'o', 'ô' => 'o', 'õ' => 'o', 'ö' => 'o', 'ő' => 'o',
        'ø' => 'o', 'ù' => 'u', 'ú' => 'u', 'û' => 'u', 'ü' => 'u', 'ű' => 'u', 'ý' => 'y', 'þ' => 'th',
        'ÿ' => 'y',
        // Latin symbols
        '©' => '(c)',
        // Greek
        'Α' => 'A', 'Β' => 'B', 'Γ' => 'G', 'Δ' => 'D', 'Ε' => 'E', 'Ζ' => 'Z', 'Η' => 'H', 'Θ' => '8',
        'Ι' => 'I', 'Κ' => 'K', 'Λ' => 'L', 'Μ' => 'M', 'Ν' => 'N', 'Ξ' => '3', 'Ο' => 'O', 'Π' => 'P',
        'Ρ' => 'R', 'Σ' => 'S', 'Τ' => 'T', 'Υ' => 'Y', 'Φ' => 'F', 'Χ' => 'X', 'Ψ' => 'PS', 'Ω' => 'W',
        'Ά' => 'A', 'Έ' => 'E', 'Ί' => 'I', 'Ό' => 'O', 'Ύ' => 'Y', 'Ή' => 'H', 'Ώ' => 'W', 'Ϊ' => 'I',
        'Ϋ' => 'Y',
        'α' => 'a', 'β' => 'b', 'γ' => 'g', 'δ' => 'd', 'ε' => 'e', 'ζ' => 'z', 'η' => 'h', 'θ' => '8',
        'ι' => 'i', 'κ' => 'k', 'λ' => 'l', 'μ' => 'm', 'ν' => 'n', 'ξ' => '3', 'ο' => 'o', 'π' => 'p',
        'ρ' => 'r', 'σ' => 's', 'τ' => 't', 'υ' => 'y', 'φ' => 'f', 'χ' => 'x', 'ψ' => 'ps', 'ω' => 'w',
        'ά' => 'a', 'έ' => 'e', 'ί' => 'i', 'ό' => 'o', 'ύ' => 'y', 'ή' => 'h', 'ώ' => 'w', 'ς' => 's',
        'ϊ' => 'i', 'ΰ' => 'y', 'ϋ' => 'y', 'ΐ' => 'i',
        // Turkish
        'Ş' => 'S', 'İ' => 'I', 'Ç' => 'C', 'Ü' => 'U', 'Ö' => 'O', 'Ğ' => 'G',
        'ş' => 's', 'ı' => 'i', 'ç' => 'c', 'ü' => 'u', 'ö' => 'o', 'ğ' => 'g',
        // Russian
        'А' => 'A', 'Б' => 'B', 'В' => 'V', 'Г' => 'G', 'Д' => 'D', 'Е' => 'E', 'Ё' => 'Yo', 'Ж' => 'Zh',
        'З' => 'Z', 'И' => 'I', 'Й' => 'J', 'К' => 'K', 'Л' => 'L', 'М' => 'M', 'Н' => 'N', 'О' => 'O',
        'П' => 'P', 'Р' => 'R', 'С' => 'S', 'Т' => 'T', 'У' => 'U', 'Ф' => 'F', 'Х' => 'H', 'Ц' => 'C',
        'Ч' => 'Ch', 'Ш' => 'Sh', 'Щ' => 'Sh', 'Ъ' => '', 'Ы' => 'Y', 'Ь' => '', 'Э' => 'E', 'Ю' => 'Yu',
        'Я' => 'Ya',
        'а' => 'a', 'б' => 'b', 'в' => 'v', 'г' => 'g', 'д' => 'd', 'е' => 'e', 'ё' => 'yo', 'ж' => 'zh',
        'з' => 'z', 'и' => 'i', 'й' => 'j', 'к' => 'k', 'л' => 'l', 'м' => 'm', 'н' => 'n', 'о' => 'o',
        'п' => 'p', 'р' => 'r', 'с' => 's', 'т' => 't', 'у' => 'u', 'ф' => 'f', 'х' => 'h', 'ц' => 'c',
        'ч' => 'ch', 'ш' => 'sh', 'щ' => 'sh', 'ъ' => '', 'ы' => 'y', 'ь' => '', 'э' => 'e', 'ю' => 'yu',
        'я' => 'ya',
        // Ukrainian
        'Є' => 'Ye', 'І' => 'I', 'Ї' => 'Yi', 'Ґ' => 'G',
        'є' => 'ye', 'і' => 'i', 'ї' => 'yi', 'ґ' => 'g',
        // Czech
        'Č' => 'C', 'Ď' => 'D', 'Ě' => 'E', 'Ň' => 'N', 'Ř' => 'R', 'Š' => 'S', 'Ť' => 'T', 'Ů' => 'U',
        'Ž' => 'Z',
        'č' => 'c', 'ď' => 'd', 'ě' => 'e', 'ň' => 'n', 'ř' => 'r', 'š' => 's', 'ť' => 't', 'ů' => 'u',
        'ž' => 'z',
        // Polish
        'Ą' => 'A', 'Ć' => 'C', 'Ę' => 'e', 'Ł' => 'L', 'Ń' => 'N', 'Ó' => 'o', 'Ś' => 'S', 'Ź' => 'Z',
        'Ż' => 'Z',
        'ą' => 'a', 'ć' => 'c', 'ę' => 'e', 'ł' => 'l', 'ń' => 'n', 'ó' => 'o', 'ś' => 's', 'ź' => 'z',
        'ż' => 'z',
        // Latvian
        'Ā' => 'A', 'Č' => 'C', 'Ē' => 'E', 'Ģ' => 'G', 'Ī' => 'i', 'Ķ' => 'k', 'Ļ' => 'L', 'Ņ' => 'N',
        'Š' => 'S', 'Ū' => 'u', 'Ž' => 'Z',
        'ā' => 'a', 'č' => 'c', 'ē' => 'e', 'ģ' => 'g', 'ī' => 'i', 'ķ' => 'k', 'ļ' => 'l', 'ņ' => 'n',
        'š' => 's', 'ū' => 'u', 'ž' => 'z'
    );

    // Make custom replacements
    $str = preg_replace(array_keys($options['replacements']), $options['replacements'], $str);

    // Transliterate characters to ASCII
    if ($options['transliterate']) {
        $str = str_replace(array_keys($char_map), $char_map, $str);
    }

    // Replace non-alphanumeric characters with our delimiter
    $str = preg_replace('/[^\p{L}\p{Nd}]+/u', $options['delimiter'], $str);

    // Remove duplicate delimiters
    $str = preg_replace('/(' . preg_quote($options['delimiter'], '/') . '){2,}/', '$1', $str);

    // Truncate slug to max. characters
    $str = mb_substr($str, 0, ($options['limit'] ? $options['limit'] : mb_strlen($str, 'UTF-8')), 'UTF-8');

    // Remove delimiter from ends
    $str = trim($str, $options['delimiter']);

    return $options['lowercase'] ? mb_strtolower($str, 'UTF-8') : $str;
}

How to use:

echo url_slug("olá titulo do meu post", ['transliterate' => true]);
ola-titulo-do-meu-post

Or a lean function using the iconv library ( source ) :

function slugify($text)
{
    $text = iconv('utf-8', 'us-ascii//TRANSLIT', $text);
    return strtolower(preg_replace('/[^A-Za-z0-9-]+/', '-', $text));
}

echo slugify("olá titulo do meu post");
// Resultado: ol-a-titulo-do-meu-post

Additional Information

Using Permanent Links (Wordpress)

You can create a field in the table, and save your encrypted id, then when you get the data from the DB you compares the two, like this:

$idCriptografada = md5(1); // o id seria 1

$sql = mysql_query("SELECT * FROM tabela WHERE id_criptografado='".$idCriptografada."'");

This way you could get the data.

NOTE: I used md5() as a example, you can use any other method you want.