Question

I am developing a PHP script and I have a table like this:

TABLE_CODE
   code  varchar  8
   name  varchar  30

this code column has to be a code using random letters from A to Z and characters from 0 to 9 and has to be unique. all uppercase. Something like

A4RTX33Z

I have create a method to generate this code using PHP. But this is a intensive task because I have to query the database to see if the generated code is unique before proceeding and the table may have a lot of records.

Because I know mySQL is a bag of tricks but not having advanced knowledge about it now, I wonder if there’s some mechanism that could be built in a table to run a script (or something) every time a new record in created on that table to fill the code column with a unique value.

thanks

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edit: What I wonder is if there’s a way to created the code on-the-fly, as the record is being added to the table and that code being unique.

Answer 1

Better generate these codes in SQL. This is 8-character random “Promo code generator”:

INSERT IGNORE INTO 
TABLE_CODE(name, code)
VALUES(
    UPPER(SUBSTRING(MD5(RAND()) FROM 1 FOR 8)), -- random 8 characters fixed length
    'your code name'
)

Add UNIQUE on code field as @JW suggested, and some error-handling in PHP, because sometimes generated value may be not UNIQUE, and MySQL will raise error in that situation.