TSQL Tuesday

T-SQL Tuesday 146: Where should business logic reside?

I am trying to get started on blogging again this year…T-SQL Tuesday came in handy with a great topic. This month’s host is Andy Yun(t |b). Andy’s challenge for us is to write about some notion ‘something you’ve learned, that subsequently changed your opinion/viewpoint/etc. on something. ‘

There are many things on which I’ve changed my opinion in my journey as a data professional. For this blog post, I picked a common one – where business logic should reside. During my years as a production DBA – there was (and probably is) a hard-held belief that databases are meant for CRUD operations only and business logic belongs in the application/middle tier. This belief has its place – DBAs don’t like debugging code that is application-specific, or be tasked with why data looks a certain way or what code caused it. Business logic can also be very complex and get deeply embedded in one place (the database). I have believed in this and fought for this at most places I’ve worked as a DBA.

Over time though, my opinion has changed. The fact that DBAs have to learn some degree of programming to survive today’s world has a lot to do with it. Also, I started to understand the nature of business logic better. I learned that a lot of things like foreign key constraints, not null constraints, triggers actually have to do with business logic and how the business defines its data. Databases usually outlive applications and less work is necessary when there is a move to a new application layer. It is much faster to make changes on the database side and roll it out compared to most application changes. It also offers single-point control of business logic, as opposed to it spread all over the place in applications.

And last but not least – learning business logic makes a person an important asset to the business. Most DBAs complain about being ‘just firefighters’…if we know business logic and have control over that, that makes us more than that – it makes us an important asset, in addition to helping us learn more programming as part of that process.

I do realize that there are cons to putting business logic in the database too. It can be very complex in some cases. The business may not have enough people to maintain it. It is a single point of control, therefore a single point of failure too if one looks at it that way. But now I believe there are more advantages to it than disadvantages. Thank you, Andy, for hosting.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.