How To Guarantee Concurrent Threads Dont Get The Same Value In Mysql?

Lets say the last row in my orders table is Order_ID Product 555 Apple How can I make sure that 2 orders happening at the exact time wont get the same same Order_I

Solution 1:

I believe that you are 'hardcoding' the order_id + 1...

Please use Auto_increment in your table and it will guarantee you it wont be any order_id repeated

http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html

In your case, make a copy of your table (back-up), alter your table and add an auto_increment then import again

Solution 2:

Define the Order_ID column with the AUTO_INCREMENT attribute and let MySQL assign values for you (that you then retrieve by asking the driver for the last_insert_id after a successful insertion):

ALTERTABLE orders MOFIFY Order_ID BIGINT UNSIGNED NOTNULL AUTO_INCREMENT;

Then, to insert records you simply don't provide an Order_ID value and it will automatically be assigned:

INSERTINTO orders (Product) VALUES ('Apple');