looping 4 digits number

[robert_gsfame]

I have used 4 digits number which is being set randomly together with user's fistname to be inserted into my database, to be their user ID

 

assume i have user and his firstname is JOE

so i will have this 4 digits number attached together with his firstname 4561JOE

 

what if i have different user with the same fistname as JOE...

how can i prevent this user of having the same 4 digits like what the first JOE had

 

in simple words: i dont want second guy get the same ID with the first one (4561JOE)

 

how can i do it using rand()

 

thx

[Sergey Popov]

I would make a loop with say 100 iterations, and on each iteration I would generate random 4 digit code and check if CODE + FIRSTNAME already exists in the db (or in array, if there are no too much users). Once the code with no matches found, exit from loop with break.

[ignace]

Just create an ordinary AUTO_INCREMENT field with ZeroFill show their userid as

 

SELECT concat(id, username) AS UID ..

 

CREATE TABLE .. (

  id INT ZEROFILL NOT NULL AUTO_INCREMENT

  ..

 

This way you'll get:

 

0001IGNACE

0002ROBERT

 

Or create your table and set the start index at 1000 That way you'll get:

 

1000IGNACE

1001ROBERT

1002SERGEY

 

CREATE TABLE .. (

  ..

) AUTO_INCREMENT = 1000