[czx4f4bd]

I wonder if there's been any observable correlation between JSON support in the major SQL databases and the decreased (or increased?) adoption of NoSQL document databases like MongoDB. It would be interesting to do some bulk analysis on GitHub commits to compare their use over time.

[hn_throwaway_99]

Just one bit of personal experience, but for me it was a significant reason. In most cases you want objects to have highly structured data (e.g. for joins and queries) and in other cases you just want "a bunch of semi-structured stuff". Sure, DBs always had blobs and text, but JSON is really what you want a lot of the time.

There's also a good article by Martin Fowler about how "NoSQL" was really "NoDBA" for a lot of folks, and I definitely saw that dynamic. JSON fields can also be a good middle ground here, where a DBA can insure good "structural integrity" of your schema, but you don't need to go through the hassle of adding a new column and schema update if you're just adding some "trivial" bit of data.

[tracker1]

The canonical example for me, is when you want to store/use additional payment processor details for a transaction... If it's direct CC, PayPal, Amazon Payments etc. Relationally you only really care that the amount of the transaction was sent/received/accepted. But you may want to store the additional details, without a series of specific tables per payment processor. If you need to see the extra details that can still be done at runtime.

Another good example is for generalized classified ads, different categories may have additional details, but you don't necessarily want to create the plethora of tables to store said additional details.

[throwaway894345]

Honestly, I pretty much always want structure. The reasons I've opted for NoSQL are almost always that cloud providers offer it for practically free while managed SQL databases are wayyyy more expensive. The nice thing about JSON is that it's a lot more ergonomic, but not because of the lack of typing--I would absolutely use a database that let my write reasonable type constraints for JSON columns. (I realize that you're talking about why most people use NoSQL and I'm remarking about why I use NoSQL).

Some other controversial thoughts: SQL itself is a really not-ergonomical query language, and also the lack of any decent Rust-like enum typing is really unfortunate. I know lots of people think that databases aren't for typing, but (1) clearly SQL aspires toward that but gives up half way and (2) that's a shame because they have a lot of potential in that capacity. Also while you can sort of hack together something like sum types / Rust enums, it's a lot of work to do it reasonably well and even then there are gaps.

[munk-a]

Every ecosystem I've ever worked in has had good tooling for managing DB migrations (and in some cases I've been the one to add it). It's trivial to write a migration to ALTER TABLE bar ADD COLUMN foo and I think keeping structure explicit is generally quite beneficial for data safety even if you're not doing fancy things. DBAs are great but most companies simply don't need one - you can just get by with some pretty rudimentary SQL and skill up as needed.

Assuming you've got good integration test coverage of the database schema alterations end up taking a minuscule amount of time and if you lack test coverage than please reconsider and add more tests.

[threeseed]

MongoDB remains the 5th most popular database: https://db-engines.com/en/ranking

And there are four major reasons still to choose MongoDB over something like PostgreSQL.

a) PostgreSQL has terrible support for horizontal scalability. Nothing is built-in, proven or supported.

b) MongoDB has superior ability to manipulate and query the JSON.

c) MongoDB is significantly faster for document-attribute updates.

d) MongoDB has better tooling for those of us that prefer to manage our schema in the application layer.

[paulddraper]

By the time you need to shard PostgreSQL (billions of records?), you have lots and lots of resources to overcome that difficulty, a la Notion.

[throwaway2990]

a) not true b) not true c) not true d) not true e) a lot of people have no idea json support exists in PostgreSQL.

[pjmlp]

PostgreSQL isn't the only RDMS to chose from.

[sverhagen]

You would have to tell the decreased adoption of NoSQL due to JSON support in major SQL databases apart then from the decreased adoption of NoSQL due to the hype being over...