PHP Unlimited class get top class category id,php Top _php Tutorials

PHP Unlimited class get top class category id,php top

There is such a table, the ID is the classification of the Id,name is the classification name, PID is the ID of the parent category.

Now there is a classification ID, the program to find its superior superiors ... The ID of the classification is simply to find the ID of the top-level category.
For example, "Fresh fruit" ID is 13, corresponding to the parent class ID is 5, and 5 of the parent ID is no parent class, that is, top-level classification.

Previously young and not sensible, always want to return to find, and then cache the results to solve performance problems.
Later, I tried to cache the entire table, and then recursively look it up.
And then ... There seems to be less chance of encountering an infinite class classification ...

Recently a colleague asked me how to solve this problem "gracefully".
So I brainwave, there is the following solution:

<?php$sql = "SELECT ID, PID from tablename";//query results are processed into the following array format $arr = [  //id = pid  1 = 0,  //omitted. ..  5 = 1,  //omitted ...  The 5];//recommended to cache this array $id = 13;while ($arr [$id]) {  $id = $arr [$id];} echo $id; 1

I have to say: it's so elegant! Even I admire myself, colleagues are pleasantly surprised, tears.
Because he wrote dozens of lines of loops and then judged the recursive code, I replaced it with two lines of code ...

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http://www.bkjia.com/PHPjc/1109173.html www.bkjia.com true http://www.bkjia.com/PHPjc/1109173.html techarticle PHP Unlimited class get top class classification id,php top has such a table, ID is classified id,name is the classification name, PID is the ID of the parent category. Now there is a category ID, the program to find it ...

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