RESULTS
Key takeaways
Class 2 is not canceled
An attachment isn't always a copy
Relationships and constraints are defined by the developer in both SQL and NoSQL. MongoDB provides validators and unique constraints, but not foreign keys.
"Owned," "historical snapshot," and "current copy" have different meanings. A copy requires a source, an update, and a lag.
There's always a plan
The second factor is price
In MongoDB, the schema is validated by $jsonSchema. The Redis key convention is documented in the code and documentation; Redis itself does not validate it.
Memory, performance, consistency, recovery. “Faster” without measurements isn’t an argument.
Exercise 3. Designing and Populating NoSQL Databases
Required: Local MongoDB + Redis mini-lab — 1–2 collections with a validator (± test), projection, and $set; profile hash; TTL chain; ties and nil; seed repetition; and a recovery plan. The project may remain on PostgreSQL—provided there is a justification and a condition for review. 5 criteria × 2 = 10 points.