Unique order IDs

[Anon]

Anyone with a proven technique to generate unique order IDs for a shopping cart system? I was thinking about auto incrementing the order IDs but there maybe an insert timing issue that I am concerned about. Anyways, I'm still thinking of an approach. Any help is greatly appreicated.

[vsego]

Check uniqId() function. :-)

[Anon]

Let the dbms do it for you. The specific manner is, alas, db-specific, since the sql standard does not include anything on this subject, but every real dbms provides such a function. With mysql, it's simply a matter of adding the 'auto_increment' attribute to the column definition. With postgresql, you can use a column type of 'serial'. And so forth.

There is never a problem of duplicate id's using this capability, though of course you can have gaps in the sequence if an INSERT fails or a row is subsequently deleted (but that would be true of any method of generating ID's).

[[deleted]]

The auto_increment method works because the number that is generated is remembered by the database on a per-connection basis.
If you insert a record and get value 3, somebody else may open a connection, insert a record and get 4, but you will still see 3 because that is what you created using your connection.

[sujithnair]

Hi,
I would suggest a php generated auto id rather than a dbms one. go for uniqid(). U can give it a prefix if u wish, viz, $id=uniqid ("A");
Here 'A' is the prefix.

good luck

Sujith

[[deleted]]

Only three minor problems that make uniqid() uselessin this case (and therefore just about everywhere):

1. It's only unique on single machines with a single CPU. Dual+ CPU machines can literally execute functions at the same time, and thus get the exact same ID. The same goes for two seperate machines.

2. uniqid() returns a string, which means it will order alphabetically, not numerically, giving all sorts of exciting problems.

3. A 13 character alphanumaric number is way too difficult to type, and when it comes to ordernumbers you'll be typing quite a few while you are processing orders.

In short: Use a database generated number, because that IS unique, always.

[vsego]

I kinda misunderstood the original question. Yes, DBMS is the way.

Thanx for the correction, guys!

[Anon]

Thank you all for the overwhelming response. I have decided to use MySQL built in auto_increment feature (which is my original approach). This approach will ensure less errors in the long run since MySQL is very stable up to this point. Again, thank you all.