Stupid simple database migration management script

update_db.sh

cd "$(dirname "$0")"

DB_USER="${DB_USER:-root}"
DB_PASS="${DB_PASS}"
DB_HOST="${DB_HOST:-localhost}"
DB_NAME="${DB_NAME}"

mysql_run() {
        mysql -u"$DB_USER" -p"$DB_PASS" -h"$DB_HOST" "$DB_NAME" "$@"
}

mysql_run -e "CREATE TABLE IF NOT EXISTS migrations (filename VARCHAR(128) PRIMARY KEY, timestamp TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP)"

for i in *.sql; do
        already_applied=$(mysql_run -e "SELECT filename FROM migrations WHERE filename = '$i'")

        if [ ! -n "$already_applied" ]; then

                if cat "$i" | mysql_run; then
                        echo "$i correctly applied"
                        mysql_run -e "INSERT INTO migrations (filename) VALUES ('$i')"
                else
                        echo "!! Failed to apply $i"
                fi
        else
                echo "$i already applied"
        fi
done