Haskell binding to the ODBC API, aimed at SQL Server driver


Version on this page:0.2.5
LTS Haskell 18.28:0.2.6
Stackage Nightly 2021-06-14:0.2.5
Latest on Hackage:0.2.6

See all snapshots odbc appears in

BSD-3-Clause licensed
Maintained by [email protected]
This version can be pinned in stack with:odbc-0.2.5@sha256:096cab4f7c10eb1f3320d49b5c5944e4a402a863e091c489ab48bc3d8af4b8cb,1990

Module documentation for 0.2.5

odbc Build Status Build status

Haskell binding to the ODBC API, with a strong emphasis on stability, testing and simplicity.

Platform and database support

The following database drivers are tested against in CI:

  • Microsoft SQL Server 2017

The following operating systems are tested against in CI:

  • Windows Build status
  • Linux Build Status

I develop and test this library on OS X, but currently do not have a reliable way to run Microsoft SQL Server on Travis CI.

How ODBC works

ODBC is a C API that is split into a manager and a driver.

On Windows, there is an ODBC manager that comes with the OS. On Linux and OS X, the unixODBC package provides the same functionality.

Separately, for each database type, you have driver packages. When you provide a connection string, like this:

ODBC_TEST_CONNECTION_STRING='DRIVER={ODBC Driver 13 for SQL Server};SERVER=;Uid=SA;Pwd=Passw0rd;Encrypt=no'

The DRIVER tells the ODBC API which library to use. In this case, it’s the recent SQL Server driver provided by Microsoft. Then, ODBC functions like SQLDriverConnectW will call that library.

How to connect to Microsoft SQL Server

In recent years, Microsoft has released binary drivers for SQL Server for Windows, Linux and OS X, with a guide for each operating system. That guide for the latest and greatest official Microsoft driver is here.

You can use the SQL Server docker image to easily run SQL Server anywhere in a few seconds.

I have tested the OS X instructions on my own machine. This project’s Dockerfile follows setup instructions for Linux, and the AppVeyor file follows the setup instructions for Windows.

There is a test program that comes with the package called odbc which accepts a connection string as its argument. You can use this to test your connection easily.

(Use 17 instead of 13 if that’s the driver you installed.)

$ stack exec odbc 'DRIVER={ODBC Driver 13 for SQL Server};SERVER=;Uid=SA;Pwd=Passw0rd;Encrypt=no'
> create table foo (i int)
Rows: 0
> insert into foo values (123123123)
Rows: 0
> select * from foo
Rows: 1

Check your package is working

You can spin up a SQL Server in docker and connect to it with the trivial binary odbc that comes with this package:

$ docker run --net=host -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=Passw0rd' -d mcr.microsoft.com/mssql/server:2017-CU8-ubuntu
Unable to find image 'mcr.microsoft.com/mssql/server:2017-CU8-ubuntu' locally
2017-CU8-ubuntu: Pulling from mssql/server
4fa80d7b805d: Pull complete
484dd0f2fbdc: Pull complete
47004b22ec62: Pull complete
b70745c852a2: Pull complete
718060832ef2: Pull complete
5594e4e5950b: Pull complete
5b67719e2956: Pull complete
7d648891de3f: Pull complete
e0d1b3db20c8: Pull complete
ded313a21911: Pull complete
Digest: sha256:e1708b7d3aaf4a693ef8785f15a8b4d082939681e373c4090fd0b294d1501e57
Status: Downloaded newer image for mcr.microsoft.com/mssql/server:2017-CU8-ubuntu

$ stack exec odbc 'DRIVER={ODBC Driver 17 for SQL Server};SERVER=;Uid=SA;Pwd=Passw0rd;Encrypt=no'
> select 2 * 3;
Rows: 1

Common issues

Can’t open lib ‘ODBC Driver 13 for SQL Server’

If you see an error like this:

[unixODBC][Driver Manager]Can't open lib 'ODBC Driver 13 for SQL Server' : file not found

Then you might be trying to use the wrong driver. You might have installed version 17, so change the string to ODBC Driver 17 for SQL Server.

If it still says this, you might have to configure an odbcinst.ini file:

[ODBC Driver 17 for SQL Server]
Driver = <driver_path>

In Nix, this might be where <driver_path> is the result of evaluating ${nixpkgs.unixODBCDrivers.msodbcsql17}/lib/libmsodbcsql-17.7.so.1.1".

Which would need the following packages available:

  • nixpkgs.freetds
  • nixpklgs.unixODBC
  • nixpkgs.unixODBCDrivers.msodbcsql17

Data source name not found and no default driver specified

If you see an error like this:

[unixODBC][Driver Manager]Data source name not found and no default driver specified

This is a terrible error message. If passing your DSN via a shell environment variable or argument, check that your input string isn’t quoted e.g. "Driver=.." instead of Driver=.. due to silly shell scripting quoting issues.

Terminating with uncaught exception of type

If you see an error like this on OS X with driver version 17,

libc++abi.dylib: terminating with uncaught exception of type
std::runtime_error: collate_byname::collate_byname failed to construct
for C/en_AU.UTF-8/C/C/C/C

use driver 13 or see here for more detail.


  • Spencer Janssen
  • Yo Eight
  • Marco Z