Where is orders_id created.

We are trying to do create a script that keys off the order id. So my question is what script in Zen Cart creates the Order Id. --- orders_id in the _orders table

The database generates the orders_id value when the new record is inserted as part of the create() method in the order class.
The smartest way to extend that is to hook the NOTIFY_ORDER_DURING_CREATE_ADDED_ORDER_HEADER notifier point by adding your own custom observer class to take the passed array of data (containing the new order id and other info) and use it as part of your custom code requirements. That way you don't need to touch the order class PHP file AT ALL.

DrByte:

The database generates the orders_id value when the new record is inserted as part of the create() method in the order class.
The smartest way to extend that is to hook the NOTIFY_ORDER_DURING_CREATE_ADDED_ORDER_HEADER notifier point by adding your own custom observer class to take the passed array of data (containing the new order id and other info) and use it as part of your custom code requirements. That way you don't need to touch the order class PHP file AT ALL.

Forgive me if I appear to be slack/lazy for asking, but are there any tutorials available that provides more details into how to add an 'observer class'?
For various reasons, I've never had need to look into this aspect of zencart before now, but I'm currently working on a couple of things whereby if I'm not mistaken this could make things a whole lot easier for me.

Thanks
Rod

RodG:

Forgive me if I appear to be slack/lazy for asking, but are there any tutorials available that provides more details into how to add an 'observer class'?
For various reasons, I've never had need to look into this aspect of zencart before now, but I'm currently working on a couple of things whereby if I'm not mistaken this could make things a whole lot easier for me.

Thanks
Rod

http://www.zen-cart.com/forum/showthread.php?t=32443

Further to gilby's good suggestion, there are wiki articles, and lots of current version addons use them too. And I've posted many complete working examples in answers to various forum posts.