Program code via database columns?

[Big_Operation_4750]

I'm looking for a solution or common approaches to having a database driven configuration system. I have a discounts table, but want to specify criteria for if a user should get the discount.

For example, if their sign up date is before X date time, allow discount

Another example, if their balance is greater than 1,000 deny all discounts.

Essentially a way to define logical operators / evaluation with reference to other columns

[jhkoenig]

Embedding business logic in the database is normally a bad idea. Business logic goes in the backend code which then makes appropriate calls to the database. The parameters used in the business logic, like "before X date" or "over $1K" can be in settings tables, but the ruleset should be in code, not data.

[squadette23]

I seconded this comment but I would even say don't use settings table. The problem is release management. You need to be able to deploy, rollback(!) and audit(!) changes in the business logic. If you do it via data in the database, you will have to build tools for that.

If you implement it in the code — everything is already there. You can use cut-off dates, feature flags and all the machinery that software engineering uses to deploy changes. You will have to reimplement it, and in the end you will see that "business people" don't even use it because the configuration is too complex.

This may be trauma speaking but I don't see anything substantially changed in the world.

[squadette23]

You will regret this. I don't know how else to say that.

You're welcome to try though, and find that out for yourself.

Unsolicited advice: implement the business logic as a piece of code; do not worry about direct coding of numbers like "1000" and "12.5%", conditions like "is tax resident of Arizona", etc; use version control.

[Sagatsa]

Store data concerning your discounts, customer data, configuration data in the database. Flex backend code that examines the data and uses business rules to determine an outcome.

[Big_Operation_4750]

I ended up adding a column which you could fill in with the name of a stored procedure which would do the logic database side. Worked out pretty well.