Saving data in hexadecimal in the database

PHP already has its own functions for this:

string hex2bin ( string $data )

which converts the string hehadecimal passed in the parameter $data into a binary format, which can be saved in a BLOB in the database, or convert data from a Varchar to string , if you are storing in hex but using the data in bytes ...

... and also the

string bin2hex ( string $str )

which converts the string into $str and returns the corresponding hexadecimal, so when you retrieve the data from BLOB , you can convert them back to hex, or if you are using "ao otherwise, you can take data in bytes and use this function to convert the data to a string hex, which can be stored in a Varchar.

To use them, it depends on your case study. The important thing is to know that when you get the data in hexadecimal, you can pass them to binary with hex2bin , effectively reducing its space by 50%, to store a BLOB in the database, and when recovering data from DB, just use bin2hex to have the data in hex again.

Examples:

<?php
   $data = '546573746520646520636f6e76657273616f';
   echo hex2bin( $data );
?>

Output:

Teste de conversao

<?php
   $data = file_get_contents( 'teste.jpg' );
   echo bin2hex( $data );
?>

Output:

FFD8FFE102DE45786966000049492A00080000000F000001030001000000100A...