问在PHP和MySQL中如何避免SQL注入，同时在文本区换行？

EN

<textarea name"description" id="description" rows="4" cols="50">
//In The text area the user enter the text. Here I want if user gives html links then links becomes text and if user give line break then line break store in the database and I can get back as it is how user submitted the form. Also I want to store data securely for avoiding sql injection but dont have the exact idea how to do it.
</textarea>

$text = $_POST['description'];
$text = htmlentities($text); // Here I want to remove html entities for avoiding sql injection
$text = mynl2br($text);
// Now Fire Insert Query All the data save but while retrieving the data I am not able to get line break and turning links to the text.


function mynl2br($text) { 
   return strtr($text, array("\r\n" => '<br />', "\r" => '<br />', "\n" => '<br />')); 
}