Dynamic Discount Codes - turning them on and off?

I was checking this out - http://www.webassist.com/forums/posts.php?id=17160 - as a way of implementing dynamic discount codes so that my client can add / edit their own discounts on their website, however I'm not clear on exactly how these are turned on/off.

In the above linked post you recommend...

Originally Said By: rob75685

  1) Create a table in your database to hold the coupon codes. it should have a structure similar to:
couuponID - Auto Number, Primary key Column.
couponCode - varchar
couponAmount - double  

In order to give my client control over when these are available on their site, shouldn't there be an additional field, say couponOnOff - tinyint (1 for yes, 2 for no), so that we could filter the recordset to only make available codes that the client has decided to turn on?

I'd like to set up an Input and Update form in a custom admin area so that my client can create their own discounts and also edit existing discounts.

Would appreciate your advice on how best to implement as I'm still not clear how doing this can override/write to eCart's set Discount rules.
Thank you.
NJ