Monadic interface to sqlite

The Lemonade Sqlite project aims at providing high-level, easy to use, monadic bindings for sqlite3 in OCaml.

Features

• Provide detailed error descriptions and easy error management by performing database operations in a success monad.

• Query rows as a monadic stream. A monadic stream is similar to a normal stream but reading from the stream is performed in the success monad, thus conveying neatly error conditions to the application level.

• Insert rows read from a monadic stream. This allows to easily map complex data structures to the database rows scattered through several tables, because it easy to combine streams together.

• Optionally initialise the database with a SQL script when creating it.

These techniques are illustrated by the example example/BatchCollection.ml implementing operations to read and write items of batch job journal to a database. In this example, a journal of batch jobs, describing requests (table batch_index) the details of the corresponding query jobs (table batch_query) and the details of the computed answer (table batch_answer) is randomly generated, written to the database and retrieved.

Setup guide

It is easy to install Lemonade Sqlite using opam and its pinning feature. In a shell visiting the repository, say

% autoconf
% opam pin add lemonade-sqlite .

It is also possible to install Lemonade Sqlite manually. The installation procedure is based on the portable build system BSD Owl Scripts written for BSD Make.

1. Verify that prerequisites are installed:

   • BSD Make
   • BSD OWl
   • OCaml
   • Broken
   • Mixture
   • Lemonade
   • GNU Autoconf

2. Get the source, either by cloning the repository or by exploding a distribution tarball.

3. Optionally run autoconf to produce a configuration script. This is only required if the script is not already present.

4. Run ./configure, you can choose the installation prefix with --prefix.

5. Run make build.

6. Optionally run make test to test your build.

7. Finally run make install.

Depending on how BSD Make is called on your system, you may need to replace make by bsdmake or bmake in steps 5, 6, and 7. The GNU Make program usually give up the ghost, croaking *** missing separator. Stop. when you mistakingly use it instead of BSD Make.

Step 7 requires that you can su - if you are not already root.

Michael Grünewald in Bonn, on Mar 16, 2016