A parser, pretty printer, and type checker for SQL written in Haskell. Supports PostgreSQL SQL and PL/pgSQL syntax. BSD licensed.

This is the documentation for version 0.4.0. Documentation for other versions is available here: http://jakewheat.github.io/hssqlppp/.

Purpose

Possible uses of this library include:

• type-checker can help with SQL development and catch bugs which aren't statically detected by Postgres
• generating SQL code programmatically/ generating SQL from some other source
• transforming SQL code, possibly using quasiquoting, e.g. writing PL/pgSQL with less boilerplate, or optimisation rewrites
• viewing the catalog produced by some SQL code

With some extra work:

• generating documentation for SQL code
• support running one dialect of SQL on a different DBMS using automatic translation - portable SQL
• typesafe database access from Haskell
• lint or semantic analysis for SQL or PL/pgSQL

Status

Pre-alpha. Support for parsing SQL is patchy, but not too bad. Supports queries/DML and DDL. Here is an extract from the parsing tests which gives some examples of what can currently be parsed:

• Parsing examples

The type checker is currently still being fixed after some reworking of parsing and ast types. It should handle a lot of queries and dml fine though.

Extract from the type checking tests:

• Type-checking examples

Currently limited support for quasiquoting, here are the extracts from the tests:

• Quasiquotation examples

The pretty printer should support everything the parser supports (i.e. it pretty prints code which both the parser and Postgres understand).

Catalog information is limited, supports the type checking. Some information is collected on scalar types, domains, composite types, casts, tables, views and functions.

Installation

This project is currently developed on GHC 7.2.1. 7.0.x should be fine, 6.12.x might take a small amount of work.

To install use

cabal install hssqlppp

Documentation

Haddock docs

Examples

Some notes on hacking on hssqlppp itself

Links

Homepage: http://jakewheat.github.com/hssqlppp/

Hackage: http://hackage.haskell.org/package/hssqlppp

Repository: https://github.com/JakeWheat/hssqlppp

Changes: https://github.com/JakeWheat/hssqlppp/blob/master/CHANGES

Reporting issues and feature requests

Use the github issue tracker. Please supply an example of SQL which doesn't parse/typecheck correctly where relevant.

https://github.com/JakeWheat/hssqlppp/issues

Provisional future plans

• parameterized statements/typesafe haskell access
• some simple syntax extension support for SQL
• a 'compiler' command to help developing SQL
• parse most Postgres syntax, possibly other SQL dialects as well
• improve the typechecker - fix current regressions, get more sql type checking correctly
• improve the catalog - add more checking, more item types
• improve the quasi-quoting - is a bit ad hoc and limited at the moment
• documentation generator for SQL codebases

Contact

Let me know if you're using/ interested in using the library, if you have any problems, bug reports, or suggestions, etc.. All contributions, comments and criticism welcome:

jakewheatmail@gmail.com