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https://github.com/paurkedal/ocaml-caqti
Cooperative-threaded access to relational data
https://github.com/paurkedal/ocaml-caqti
async database io-monad lwt mariadb ocaml postgresql sqlite
Last synced: 2 days ago
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Cooperative-threaded access to relational data
- Host: GitHub
- URL: https://github.com/paurkedal/ocaml-caqti
- Owner: paurkedal
- License: lgpl-3.0
- Created: 2014-03-18T21:11:08.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2024-12-03T09:51:32.000Z (21 days ago)
- Last Synced: 2024-12-15T04:06:27.372Z (9 days ago)
- Topics: async, database, io-monad, lwt, mariadb, ocaml, postgresql, sqlite
- Language: OCaml
- Homepage: https://paurkedal.github.io/ocaml-caqti/index.html
- Size: 2.72 MB
- Stars: 313
- Watchers: 11
- Forks: 36
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGES.md
- License: COPYING
Awesome Lists containing this project
- awesome-list - ocaml-caqti - threaded access to relational data | paurkedal | 188 | (OCaml)
README
[![CircleCI](https://circleci.com/gh/paurkedal/ocaml-caqti.svg?style=svg)](https://circleci.com/gh/paurkedal/ocaml-caqti)
## Synopsis
Caqti provides a monadic cooperative-threaded OCaml connector API for
relational databases.The purpose of Caqti is further to help make applications independent of a
particular database system. This is achieved by defining a common
signature, which is implemented by the database drivers. Connection
parameters are specified as an URI, which is typically provided at run-time.
Caqti then loads a driver which can handle the URI, and provides a
first-class module which implements the driver API and additional
convenience functionality.Caqti does not generate or analyze SQL but provides templating and uniform
query parameter handling, including encoding and decoding data according to
declared types. It is hoped that this agnostic choice makes it a suitable
target for higher level interfaces and code generators.The following drivers are available:
RDBMS | URI scheme | library | Unix | MirageOS
---------- | --------------- | -------------- | ---- | --------
MariaDB | `mariadb://` | [mariadb][] | yes | no
PostgreSQL | `postgresql://` | [postgresql][] | yes | no
PostgreSQL | `pgx://` | [pgx][] | yes | yes
SQLite3 | `sqlite3://` | [sqlite3][] | yes | noThe PGX based driver is experimental and only recommended for MirageOS.
More about the drivers below.## Documentation
### Tutorials and Examples
- The [caqti-study][] repository is a tutorial with examples, which we
will keep up to date with the latest release of Caqti. It is work in
progress; suggestions and contributions are welcome.
- [Interfacing OCaml and PostgreSQL with Caqti][BP-2018] by Bobby
Priambodo gives a gentle introduction, though the Caqti API has changed
to some extend since it was written.
- [The documented example][bikereg] in this repository can give a first
idea.### API Documentation for Stable Releases
The stable API documentation is hosted on [https://ocaml.org](), where you
can search package by name.A full Caqti release contains the following packages:
- [caqti](https://ocaml.org/p/caqti/latest):
Core libraries and blocking unix connector.
- [caqti-lwt](https://ocaml.org/p/caqti-lwt/latest):
Lwt support library and connector.
- [caqti-async](https://ocaml.org/p/caqti-async/latest):
Async connector.
- [caqti-eio](https://ocaml.org/p/caqti-eio/latest):
Experimental EIO connector.
- [caqti-miou](https://ocaml.org/p/caqti-miou/latest):
Experimental Miou connector.
- [caqti-mirage](https://ocaml.org/p/caqti-mirage/latest):
Experimental MirageOS connector.
- [caqti-driver-mariadb](https://ocaml.org/p/caqti-driver-mariadb):
Driver for MariaDB and MySQL using C bindings from [mariadb][].
- [caqti-driver-postgresql](https://ocaml.org/p/caqti-driver-postgresql):
Driver for PostgreSQL using C bindings from [postgresql][].
- [caqti-driver-sqlite3](https://ocaml.org/p/caqti-driver-sqlite3):
Driver for local SQlite3 databases using C bindings from [sqlite3][].
- [caqti-driver-pgx](https://ocaml.org/p/caqti-driver-pgx):
Experimental driver for PostgreSQL using the [pgx][] library.
- [caqti-tls](https://ocaml.org/p/caqti-tls):
TLS configuration currently only used by caqti-mirage, and only relevant
for pgx, since drivers based on C bindings have external TLS support.The connector modules provide a connect functions which receives an URI,
dispatches to an appropriate driver, and returns a connection object as a
first-class module, which contains query functionality for the database.
The application can either link against the drivers it needs or the link
against the `caqti.plugin` library in order to load the appropriate driver
at runtime.(A few package not mentioned include unreleased TLS packages and the
semi-deprecated packages
[caqti-type-calendar](https://ocaml.org/p/caqti-type-calendar/latest) and
[caqti-dynload](https://ocaml.org/p/caqti-dynload/latest).)### API Documentation for Development Snapshots
Apart from the above links, the [GitHub pages][caqti-ghpages] are updated
occasionally with a rendering from the master branch. You can also build
the API reference matching your installed version using [odig][] or run
`dune build @doc` in a Git checkout.## Running under utop
Dynamic linking does not work under utop. The workaround is to link against
the needed database driver. E.g.
```ocaml
# #require "caqti-lwt";;
# #require "caqti-driver-postgresql";;
# open Lwt.Infix;;
# open Caqti_request.Infix;;(* Create a DB handle. *)
# module Db = (val Caqti_lwt_unix.connect (Uri.of_string "postgresql://") >>= Caqti_lwt.or_fail |> Lwt_main.run);;
module Db : Caqti_lwt.CONNECTION(* Create a request which merely adds two parameters. *)
# let plus = Caqti_request.(Caqti_type.(t2 int int) ->! Caqti_type.int) "SELECT ? + ?";;
val plus : (int * int, int, [< `Many | `One | `Zero > `One ]) Caqti_request.t =
(* Run it. *)
# Db.find plus (7, 13);;
- : (int, [> Caqti_error.call_or_retrieve ]) result = Ok 20
```## Related Software
- [ppx\_rapper](https://github.com/roddyyaga/ppx_rapper) - a syntax
extension for Caqti queries, simplifying type specifications.## Sponsor
Thanks to the OCaml Software Foundation
for economic support to the development of Caqti.[caqti-ghpages]: http://paurkedal.github.io/ocaml-caqti/index.html
[BP-2018]: https://medium.com/@bobbypriambodo/interfacing-ocaml-and-postgresql-with-caqti-a92515bdaa11
[bikereg]: examples/bikereg.ml
[caqti-study]: https://github.com/paurkedal/caqti-study/
[odig]: http://erratique.ch/software/odig
[mariadb]: https://github.com/andrenth/ocaml-mariadb
[pgx]: https://github.com/arenadotio/pgx
[postgresql]: https://mmottl.github.io/postgresql-ocaml
[sqlite3]: https://mmottl.github.io/sqlite3-ocaml