mt_rand is producing the same number instead of randomizing

[scmeeker]

I've used this before and it worked fine but the mt_rand is not working properly.  It keeps producing the same number.

 

I've tested it on with the $_GET to the next page and it produces a unique code but it doesn't want to insert that number into the table, just the other same, repetitive number.

 

$transaction_id =  mt_rand() . mt_rand();
$item_email = mysql_real_escape_string($_POST[email]);
$item_first_name = mysql_real_escape_string($_POST[first_name]);
$item_last_name = mysql_real_escape_string($_POST[last_name]);
$item_street = mysql_real_escape_string($_POST[street]);
$item_street2 = mysql_real_escape_string($_POST[street_2]);
$item_city = mysql_real_escape_string($_POST[city]);
$item_state = mysql_real_escape_string($_POST[state]);
$item_zip_code = mysql_real_escape_string($_POST[zip_code]);
$item_country = mysql_real_escape_string($_POST[country]);
$username = $_SESSION['username'];
$item_id = $_GET['id'];
$item_title = mysql_real_escape_string($_POST[title]);
$item_price = mysql_real_escape_string($_POST[price]);
$item_shipping_cost = mysql_real_escape_string($_POST[shipping_cost]);
$item_in_shipping = mysql_real_escape_string($_POST[in_shipping]);
$okay = TRUE;

if ($item_country == 'United States'){
$shipping = "$item_shipping_cost";
}
else { $shipping = "$item_in_shipping    - <span class=\"submissionfont\">International Rate</span>";
}

$sql="INSERT INTO buyer (username, email, first_name, last_name, street, street_2, city, state, zip_code, country, transaction_id, date) VALUES ('$username', '$item_email', '$item_first_name', '$item_last_name', '$item_street', '$item_street2', '$item_city', '$item_state', '$item_zip_code', '$item_country', '$transaction_id', CURDATE())";

if (!mysql_query($sql))

  {

  die('Error: ' . mysql_error());

  }  
  
  $sql2="UPDATE product SET transaction_id='$transaction_id', sold='1', sold_date=CURDATE() WHERE id = '$item_id'";
  
if (!mysql_query($sql2))

  {

  die('Error: ' . mysql_error());

  } 

[gizmola]

I'm confused.  You say it produces a unique number (and you're concatenating the output of 2 calls together)?  Then you say that you have seen it's unique but it inserts the same value in the database table? 

[scmeeker]

When I run it, it does produce a new number when I tested it in the URL but it's not inserting this new random number into the "buyer" table.

 

Here is that section of the code from the previous code I posted:

 

$sql="INSERT INTO buyer (username, email, first_name, last_name, street, street_2, city, state, zip_code, country, transaction_id, date) VALUES ('$username', '$item_email', '$item_first_name', '$item_last_name', '$item_street', '$item_street2', '$item_city', '$item_state', '$item_zip_code', '$item_country', '$transaction_id', CURDATE())";

[scmeeker]

I also tried going back to change the subject line in my original post but couldn't...sorry for the confusion.

[gizmola]

echo out the $sql statement, check that it's what you expect, and run that from command line mysql or phpMyAdmin and make sure you don't have a syntax error.

[brianlange]

Remove the quotes around $transaction_id in the sql statement. It's an integer so quotes aren't necessary.

[gizmola]

Remove the quotes around $transaction_id in the sql statement. It's an integer so quotes aren't necessary.

 

Perhaps, but I doubt it considering how he's using it in the code.

[scmeeker]

It's inserting everything else into the table perfectly and outputting all the other information fine.  Like I said, I tested it with this line of code after the first two ($sql) &($sql2):

 

header("location:finalize.php?username=$username&id=$item_id&transaction_id=$transaction_id");

 

When doing this, on the next page it generated a new $transaction_id into the URL just fine.  It's just not inserting the new random number into the table....it keeps showing up as the same number (which I have no idea where it is getting that number from) even after deleting its presence from my database and resetting my server.

[gizmola]

Again, I asked you to echo out $sql before the insert and to paste it here.  Also, what is the structure of the buyer table?

[scmeeker]

When you say "echo out $sql", do you mean to make the $transaction_id echo (echo $transaction_id)before the insert table?  If so, I did and on the next page it printed a different random number.  Otherwise, I'm not sure what you meant.

 

[scmeeker]

As far as the structure of the buyers table, all the columns are listed in the Insert ($sql) that is listed except the id that is auto-incremented.  The transaction_id is an integer.  Again, I'm not sure what your asking?

[gizmola]

$sql="INSERT INTO buyer (username, email, first_name, last_name, street, street_2, city, state, zip_code, country, transaction_id, date) VALUES ('$username', '$item_email', '$item_first_name', '$item_last_name', '$item_street', '$item_street2', '$item_city', '$item_state', '$item_zip_code', '$item_country', '$transaction_id', CURDATE())";
echo $sql;
die();

[PFMaBiSmAd]

mt_rand() . mt_rand() produces a rather large number and is probably exceeding your column definition.

 

Show us the value that is being inserted (seeing it might help someone help you), show us some of the values that are being generated for $transaction_id, and show us the column definition.

[gizmola]

Ok, well there you go then.... if transaction_id is an integer then you shouldn't have the quotes around it, as brianlange suggested.  However, you also shouldn't be doing this earlier:

 

$transaction_id =  mt_rand() . mt_rand();

 

You will easily overflow the integer range on a regular basis concatenating these numbers together.  On one of my servers the max number that can be returned from mt_rand() is a signed positive integer (21474836470, so mt_rand can return anything between 0 and that number which is already the largest number in the signed integer range.

 

 

[scmeeker]

The number that keeps getting inserted into the transaction_id column is "2147483647" and this is the structure of that column:

 

transaction_id  int(200) 

 

The numbers that keep going into the URL are at this length:  6179917971979951556

 

[gizmola]

Exactly.  You are overflowing the largest number possible in the column as explained by PFMaBiSmAd and myself in the last two posts.

[scmeeker]

I changed the transaction_id "type" in mysql to Varchar and its working fine now.  Hours gone...how frustrating.

 

Thanks you for your help, it pushed me in the right direction.

[gizmola]

No worries, just make sure you have declared it to be a VARCHAR(20) to account for the maximum size of the strings you can create.