Typed SQL queries and migrations for Postgres and SQLite, on OCaml 5.

Typed SQL queries and migrations for Postgres and SQLite, on OCaml 5.

You write the SQL. You declare its parameters and rows once, and that one declaration binds the values going in and decodes the rows coming out.

opam repo add hypha https://github.com/hyphatech/opam-repository.git
opam install rowtype rowtype-postgres rowtype-migrate

Get startedReference

module S = Rowtype

type user = { id : int; name : string }

let user =
  S.map (S.t2 S.int S.text)
    ~parse:(fun (id, name) -> { id; name })
    ~print:(fun u -> (u.id, u.name))

let add_user =
  S.find ~params:S.text ~row:S.int
    "insert into users (name) values ($1) returning id"

let find_user =
  S.find_opt ~params:S.int ~row:user "select id, name from users where id = $1"

Plain SQL

No ORM, no query DSL, no ppx.

Statements

Checked against your database

Every statement described by the database from a test, without running it, so a renamed column fails a test instead of a request.

Checking statements

Postgres and SQLite

The same statements run on both.

SQLite

Migrations in the box

Plain SQL files and one command for every dialect, a library’s own migrations included.

Migrations

Failures you can act on

A refused write names its constraint, and a lost write is told from one never sent.

Errors

Any size

Rows read in the memory of one, and loads through COPY.

Bulk writes