Question

I was going through this article today.

http://vinothbabu.com/2010/05/08/update-and-insert-differences-in-syntax-is-an-inconvenience/

I was not able to understand this part of the code written by the author.

    list($sets,$cols,$values)=escape_arr($sets);

    $insert_sql=”INSERT INTO `avatars` “.implode(’,',$cols).” 
    VALUES(”.implode(’,',$values).”)”;

    $update_sql=”UPDATE `avatars` SET “.implode(’,',$sets).”
    WHERE userid=$userid LIMIT 1″;

and finally the conclusion part of the article.

Answer 1

The PHP implode turns the array of column names into a comma separated string. It does the same for the values in the INSERT statement.

$sets starts off as an associative array of column name / value pairs. This statement:

list($sets, $cols, $values) = escape_arr($sets);

reassigns the $sets variable to be a regular array containing strings like “column_name = ‘value'”. It does this with the helper function escape_arr in the article, which returns 3 arrays. Check the documentation for list if you’re unsure what it does.

Then it uses the implode function again to build one big comma separated string of the $sets array. So effectively, it builds both INSERT and UPDATE statements given an associative array containing column names as keys, and their values as well… values.

Was that the question? You can insert some var_dump statements in the code to follow what it’s doing at every step.

Edit: sorry for the messy explanation, but I gotta run for now 🙂