If you're thinking in the first terms, is a relational DB the right backing store, or wouldn't it be better to back your DB with something more like Mongo?
Do they still obtain some benefit from the schema, since from time to time the semantics of a property will change, and a schema can tell them what the current shape of the data is and guide the migration. Or would they prefer to just write a new property which does a lazy conversion from the old terms? (To an extent, I suppose the answer to this question determines the answer to the first. But I guess there's other tradeoffs to Monggo I'm not aware of, since schemalessness fills me with fear and I just don't want to look there.)
Regarding your final paragraph: I suspect that, for many apps, the choice between relational vs transparent persistency is largely determined by the team who is working on it. The "hard trick" is therefore trying to balance a strong personality with a strong view who disagrees with the rest of the team who have weaker personalities and weaker views, but who all agree on the other side of the fence. This is simply a standard management question with very little technical relevance.
I suppose it depends on whether you want schema-on-read or schema-on-write.
Even if you're working under the first model, there's still a lot an RDBMS can do to help you ensure data integrity. Largely by being less flexible. Databases like MongoDB allow for a more fexible schema, at the cost of pushing a lot of the work of ensuring data integrity into the application code.
For my part, I do a fair bit of working with databases that were built on the MongoDB of the '90s, Lotus Notes, and I've seen what they can grow into over the course of 25 years. It's not pretty. That experience has left me thinking that, while there's certainly a lot of value in the document store model, I wouldn't jump to a document store just because I don't need everything an RDBMS does. I'd only do it if I actively needed a document store.
> If you're thinking in the first terms, is a relational DB the right backing store, or wouldn't it be better to back your DB with something more like Mongo?
Certainly relational like for 90% of the cases, if not all.
The relational model is THE answer to nosql from the start (ie: it was the solution of the originals "nosql").
Is totally more flexible, powerful, dynamic, expressive... And that without talking about ACID!
You can model all "nosql" stores with tables. With limited exceptions it will work very fine for most uses...
> This is simply a standard management question with very little technical relevance.
I don't get what your are implicating here...
But nosql solutions are the ones to be suspected and the ones to requiere a harder qualifications and justifications to use. Is the wrong choice in the hands of the naive. "NoSql" is for experts and for niche/specific workloads.
If you're thinking in the first terms, is a relational DB the right backing store, or wouldn't it be better to back your DB with something more like Mongo?
Do they still obtain some benefit from the schema, since from time to time the semantics of a property will change, and a schema can tell them what the current shape of the data is and guide the migration. Or would they prefer to just write a new property which does a lazy conversion from the old terms? (To an extent, I suppose the answer to this question determines the answer to the first. But I guess there's other tradeoffs to Monggo I'm not aware of, since schemalessness fills me with fear and I just don't want to look there.)
Regarding your final paragraph: I suspect that, for many apps, the choice between relational vs transparent persistency is largely determined by the team who is working on it. The "hard trick" is therefore trying to balance a strong personality with a strong view who disagrees with the rest of the team who have weaker personalities and weaker views, but who all agree on the other side of the fence. This is simply a standard management question with very little technical relevance.