pg_jsonschema

Agree, Rust and Postgres and a perfect match. It feels so much more productive to write Postgres tooling in Rust. E.g. we already have extensions like pg_graphql[0], pg_jsonschema[1] and wrappers[2] which use pgrx. We don't have plrust on the platform yet though. Full disclosure: I'm a Rust Engieer at Supabase. [0] https://github.com/supabase/pg_graphql [1] https://github.com/supabase/pg_jsonschema [2] https://github.com/supabase/wrappers

I'd assume this might be solvable in the DB layer using CHECK constraints, possibly combined with JSON Schema validation? From quick glance, JSON Schema validation isn't built-in to Postgres, but there are third-party extensions, such as https://github.com/supabase/pg_jsonschema or https://github.com/gavinwahl/postgres-json-schema. I'm more familiar with MySQL and MariaDB, which offer it built-in: https://dev.mysql.com/doc/refman/8.0/en/json-validation-func... and https://mariadb.com/kb/en/json_schema_valid/

And lots of interesting extensions use it, like https://github.com/tembo-io/pgmq https://github.com/zombodb/zombodb https://github.com/supabase/pg_jsonschema

> In other words, there is still a (lossy) translation layer, it just happens to be in the RDBMS rather than in-app. It's not lossy if your application can guarantee a json <-> datatype roundtrip and the json is validated with jsonschema (generated by your application) In Rust it's something like this https://serde.rs/ to do the data type <-> json mapping https://docs.rs/schemars/latest/schemars/ to generate jsonschema from your types https://github.com/supabase/pg_jsonschema to validate jsonschema in your database (postgres). with this setup it's interesting (but not required) to also use https://docs.rs/jsonschema/latest/jsonschema/ to validate the schema in your application

Pretty exciting! What about optionally validating some columns with jsonschema? Perhaps using https://github.com/supabase/pg_jsonschema - is using other postgres extensions supported in FerretDB? (if not, maybe it's feasible to incorporate the code of pg_jsonschema in FerretDB?)

totally agree ""Using composite types is mildly annoying since you must wrap the composite column in parenthesis to access the field""" ^ yeah that is frustrating -- if you create domains over jsonb frequently, check out pg_jsonschema[1] as a way to express the constraints more concisely [1] https://github.com/supabase/pg_jsonschema

This is my pet peeve with SQL. I hope some day PostgreSQL gain support for native tagged unions. I have saved some links about this https://github.com/solidsnack/pg-sql-variants https://thelyfsoshort.io/variant-types-in-postgresql-c63725f... https://www.parsonsmatt.org/2019/03/19/sum_types_in_sql.html https://typeable.io/blog/2019-11-21-sql-sum-types.html Right now I think the ideal is a jsonb column (with a field that stores the tag) plus https://github.com/supabase/pg_jsonschema. But this is only usable if your language translates to/from JSON and generates json schema for you. Rust can do this with https://serde.rs/ and https://docs.rs/schemars/latest/schemars/

One of the restrictions of composite types is that they can not contain an instance of themselves. So unfortunately, this is not currently possible. I had this issue when trying to implement an AST type for pg_graphql[1] back when it was written in SQL [2]. In the end we used a JSON type which was much less constrained. That might be solvable using pg_jsonschema [3] if you really wanted to have a good time though [1] https://github.com/supabase/pg_graphql [2] https://github.com/supabase/pg_graphql/blob/34cc266da972d356... [3] https://github.com/supabase/pg_jsonschema

I'm not currently using it, but I'm strongly considering validating json in postgres with https://github.com/supabase/pg_jsonschema - which uses the https://docs.rs/jsonschema/latest/jsonschema/ Rust crate So I'm not sure if my feedback is valid but, I sure hope that the jsonschema crate follows the spec! Otherwise I'll never use jsonschema but instead something-not-exactly-jsonschema. In other words.. you better not break anything.

Sounds dumb, but I want JSON field schema validation. I added a JSON column for flexible data, and although I'm happy with its flexibility, I kinda hope I can validate the JSON data structure. Recently I just found an extension [1] and will try soon. [1] https://github.com/supabase/pg_jsonschema

pg_jsonschema is a solution we're exploring to allow enforcing more structure on json and jsonb typed postgres columns. We initially wrote the extension as an excuse to play with pgx, the rust framework for writing postgres extensions. That let us lean on existing rust libs for validation (jsonschema), so the extension's implementation is only 10 lines of code :) https://github.com/supabase/pg_jsonschema/blob/fb7ab09bf6050... happy to answer any questions!