notes.txt

notes

to solve invalid server index warning from phpmyadmin add $i = 1; to config.inc.php
to solve login error #2002 change
  $cfg['Servers'][$i]['host'] = 'localhost';
to
  $cfg['Servers'][$i]['host'] = '127.0.0.1';

print_r: prints variables in human readable format

to dump mysql schema:
 mysqldump.exe -h 127.0.0.1 -u root -p --no-data flashcards > mysql/dbdump.sql 
 
Passwords are stored as sha-256 hashes
    mysql: SELECT SHA2('abc', 256);
    php: hash("sha256", 'abc', false)

Starting the php server:
    php -S localhost:8080
    
Useful queries:
    Get all users, decks, and card counts.  Showing orphaned decks and deckless users
    OUTER JOIN must be emulated by UNIONing LEFT and RIGHT because MySQL:
    
        SELECT user_name, deck_name, count(*)
        FROM (
            SELECT users.name AS user_name,decks.name AS deck_name,decks.deckid
            FROM users LEFT JOIN decks ON users.id=decks.userid 
            UNION
            SELECT users.name AS user_name,decks.name AS deck_name,decks.deckid
            FROM users RIGHT JOIN decks ON users.id=decks.userid 
        ) AS fulljoin
            LEFT JOIN flashcards ON fulljoin.deckid=flashcards.deckid 
            GROUP BY fulljoin.deckid
    
    Delete a user, their decks, and cards:
    
        DELETE users,decks,flashcards 
        FROM users
            JOIN decks on users.id=decks.userid
            JOIN flashcards on decks.deckid=flashcards.deckid         
        WHERE users.id=4