Question

I have a problem. I have a website with people and different transactions they make to and from a fake online bank. I want to be able to store an array of each person’s transactions on my mysql database. I want each transaction to be defined as an associative array with a timestamp and the sql query that represents their transaction with the “bank”.

Then I want those, after being serialized, to be the values of a transactions array that holds all of their transactions. Then I want to serialize that and store it in the database so that later I can add a transaction by unserializing it and appending a serialized array of another transaction to it. So far this code below works except that it just overwrites the one transaction and doesn’t append a new one. I’d really appreciate any help.

Thanks in advance

function modify_transactions($row, $sql)
{
 $sql=mysql_real_escape_string($sql);
 if(isset($row["TRANSACTIONS"]))
 {
  $transactions = unserialize($row["TRANSACTIONS"]);
 }
 else
 {
  $transactions = array();
 }
 $transaction_array = array("timestamp"=>time(),"query"=>$sql);
 $transaction_data  = serialize($transaction_array);
 $transactions[] = $transaction_data;
 $transactions_upload = serialize($transactions);
 $name = $row["NAME"];
 $query = "UPDATE band.students SET TRANSACTIONS = '$transactions_upload' WHERE students.NAME = '$name'";
 mysql_query($query);
}

Answer 1

If I were you, I’d rather go for a new table where every entry would represent a transaction and that had a foreign key student_id.

That’d be much, much, much cleaner and more flexible and scalable (i.e. what if you want to show the last 3 transactions of user X? What if a user had several million transactions?).