6 ways for PHP to generate unique order numbers

Do mall type projects often need to generate a unique order number, the following to a summary!

Method One:

Return date (' Ymd '). Str_pad (Mt_rand (1, 99999), 5, ' 0 ', str_pad_left);

Method Two: Is using ...

/**

* *

UNIQID-The official said:

* Gets A prefixed unique identifier based on the "the" in Microseconds.
  /

function build_order_no ()

{return

date (' Ymd '). substr (Implode (NULL, Array_map (' Ord '), Str_split ( SUBSTR (Uniqid (), 7,), 1)), 0, 8);

Use Uniqid to get a unique string that is generated based on the current microsecond number (but his top 7 looks like a long time before it changes, so don't worry about deleting it), take the 8th to 13th place. But there are English letters in this string.
Use Ord to get his ASCII code, so there's the next step: Split the string into str_split with the array_map to manipulate it (faster).
And then return an array, KO, in the implode string, but the length of the characters are indefinite, take a few fixed before, and then add the current year and date, the method generated by the order number, the world will not have much duplication.
Of course, unless you put the server time forward, but not to be afraid, brother does not believe he will be in the same microsecond two orders, network data transmission also point time, even if you are local.

Method Three: Used before ...

The Public Function Make_order ($user _id)

{return

Mt_rand (10,99)

. sprintf ('%010d ', Time ()-946656000)

. sprintf ('%03d ', (float) microtime () * 1000)

. sprintf ('%03d ', (int) $user _id% 1000);

Method Four:

$yCode = Array (' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ');

$orderSn = $yCode [Intval (Date (' Y ')]-2011]. Strtoupper (Date (' M ')) (Dechex). Date (' d '). SUBSTR (Time (),-5). SUBSTR (Microtime (), 2, 5). sprintf ('%02d ', rand (0, 99

));

Method five generates a 24-bit unique order number

Generate 24-bit unique order number, format: YYYY-MMDD-HHII-SS-NNNN,NNNN-CC, which: yyyy= year, mm= month, dd= date, hh=24 format hours, ii= minutes, ss= seconds, nnnnnnnn= random number, cc= check code
   @date_default_timezone_set ("PRC");   while (True) {   //order date     $order _date = date (' y-m-d ');     //Order number Main (yyyymmddhhiissnnnnnnnn)     $order _id_main = date (' ymdhis ')  .
 rand (10000000,99999999);
   //Order number main length     $order _id_len = strlen ($order _id_main);
    $order _id_sum = 0;    for ($i =0;  $i < $order _id_len;  $i + +) {     $order _id_sum +=
  (int) (substr ($order _id_main, $i, 1)); &NBSP;&NBSP;&NBSP}    //Unique order number (YYYYMMDDHHIISSNNNNNNNNCC)     $order _id =   $order _id_main . str_pad (100 -  $order _id_sum % 100)  % 100,2, ' 0 '
, Str_pad_left);       if ($result  = sqlIte_query ($db, "select * from orders where order_id= ' $order _id")) {     if (Sqlite_num_rows ($result)  == 0) {     break;      }    }

Example Six

/**

* Generates 16-bit pure Digital order number

* Maximum support time to 2056-12-31 23:59:59

* * @access public

* @return

string

* * The public static function Getordersn () {return

(date (' y ') + date (' m ') + date (' d ')). Str_pad (()-Strtotime (date () Y-m-d ')), 5, 0, Str_pad_left). SUBSTR (Microtime (), 2, 6). sprintf ('%03d ', rand (0, 999));

}

Currently in use, the basic guarantee does not repeat, can use until 2056, feel that should be enough, after the need to expand