From Feature to Data Model

An interviewer says:

"A team workspace lets members create projects, assign tasks to other members, and comment on tasks."

Many candidates answer by choosing a database.

They draw tables, add indexes, and argue about whether tasks should be stored beside projects, and none of that answers the first data-model question:

What things does the product contain, what facts belong to each thing, and which of those things can a caller act on independently?

The product data model comes before the storage model.

It contains:

• entities;
• the fields owned by each entity; and