Database Design Is Product Design for Backend Engineers

Backend engineers make product decisions when they design data. Tables, indexes, constraints, and relationships decide what is easy, what is slow, and what becomes painful later.

I care about database constraints because they protect the system even when application code has bugs. The MySQL documentation is not exciting reading, but understanding indexes, transactions, isolation, and constraints saves real production pain.

One principle I like: put important truths close to the data.

ALTER TABLE payments
  ADD CONSTRAINT payments_amount_positive CHECK (amount > 0);

Application validation is good. Database protection is better when the rule must never be violated.

I learned to take database design seriously because bad data decisions become product limitations later. A missing constraint, weak relationship, or poorly chosen data type can create months of cleanup.

Indexes are also product work. If sales, support, or operations need fast filtering, the backend has to support that reality. The user does not care that the query plan is bad; they only feel a slow product.

This is why I like reviewing schema changes carefully. A migration is not just a technical file. It is a long-term contract with the system.