package yosqlite

Sqlite for OCaml with types from Yojson

There are four functions in the library:

• db_open
• db_close
• execute
• fetch

db_open and db_close are taken straight from Sqlite3 package. You could even use your own Sqlite3 db handle, these are just added for convenience.

fetch is like execute but returns list of Yojson `Assoc

This is how you would tipically use the package:

open Base
open Yosqlite

type t =
  { id: int
  ; name: string }
[@@deriving yojson]

let init db =
  db
  |> execute
       ~sql:
         {|
    CREATE TABLE animals (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      name TEXT NOT NULL
    )
  |}

let insert_animal ~name db =
  db |> execute ~sql:"INSERT INTO animals(name) VALUES(?)" ~bind:[`String name]

let find_animal ~name db =
  db
  |> fetch ~sql:"SELECT * FROM animals WHERE name = ?" ~bind:[`String name]
  |> List.hd_exn
  |> of_yojson
  |> Result.ok_or_failwith

let main =
  let db = db_open "animals.sqlite" in
  db |> init ;
  db |> insert_animal ~name:"cat" ;
  let animal = db |> find_animal ~name:"cat" in
  assert (String.equal animal.name "cat") ;
  db |> db_close |> ignore

You can also find couple of examples in the test directory.

API Reference

 val db_open : ?mode:[ `NO_CREATE | `READONLY ] -> ?uri:bool/2 -> ?memory:bool/2 -> ?mutex:[ `FULL | `NO ] -> ?cache:[ `PRIVATE | `SHARED ] -> ?vfs:string -> string -> Sqlite3.db

val db_close : Sqlite3.db -> bool/2

type binding =
 [ `Null
 | `Int of int
 | `Float of float
 | `String of string ]

val execute: ?bind:(binding list) -> sql:string -> Sqlite3.db -> unit

val fetch : ?bind:(binding list option) -> ~sql:string Sqlite3.db -> Yojson.Safe.t list