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iODBC Driver Manager

Copyright (C) 1995 Ke Jin <>
Copyright (C) 1996-2020 OpenLink Software <>
All Rights Reserved.


Copyright 1996-2019 OpenLink Software

This software is released under either the GNU Library General Public License (see LICENSE.LGPL) or the BSD License (see LICENSE.BSD).

Note: The only valid version of the GPL license as far as this project is concerned is the original GNU General Public License Version 2, dated June 1991.


While not mandated by the BSD license, any patches you make to the iODBC project may be contributed back into the project at your discretion. Contributions will benefit the Open Source and Data Access community as a whole. Submissions may be made via the iODBC Github project or via email to


Welcome to the iODBC driver manager maintained by OpenLink Software.

This kit will provide you with everything you need in order to develop ODBC-compliant applications under Unix without having to pay royalties to other parties.

This kit consists of a number of parts:

  • The iODBC driver manager. This is a complete implementation of an ODBC driver manager, released under either the GNU Library General Public License or the BSD License. We fully comply with these licenses by giving you this product in source form (as well as the binary form). You can download the latest version of the driver manager from the iODBC website.

  • A simple example, iodbctest.c, which gives you a command-line interface to SQL. You can fit this to your purposes, but at the very least this is useful for verification of your ODBC installation.

You can use either part stand-alone, if you wish.

An ODBC driver is still needed to affect your connection architecture. You may build a driver with the iODBC components or obtain an ODBC driver from a commercial vendor. OpenLink Software produces cross-platform commercial drivers as well as maintaining the iODBC distribution: evaluation copies may be obtained via download from the OpenLink Software website. Any ODBC-compliant driver will work with the iODBC Driver Manager.

See also the iODBC website for more pointers to various ODBC drivers.

Installation of run-time distribution

You probably already unpacked this distribution. The next step is to make sure that your applications can find all the dynamic link libraries. Depending on your system's implementation of dynamic link libraries, you have a number of options:

  • Install the libraries in a directory that is searched by your linker by default. Typical locations are /usr/lib and /usr/local/lib.

  • Install the libraries in some other place, and make sure that the environment variable your dynamic linker uses to find extra locations for dynamic link libraries. Most systems use the environment variable LD_LIBRARY_PATH to this end. Exceptions are AIX which uses LIBPATH and HP/UX which uses SHLIB_PATH.

If your system has a C compiler, you can verify the installation by compiling the iodbctest program. Otherwise, you may have ODBC applications installed on your system which you can use.

Configuration of run-time distribution

The iODBC driver manager looks for a file ~/.odbc.ini, where the tilde stands for the user's home directory. This file only contains a default section where you can select which driver library to use. Copy the odbc.ini file from the examples directory to ~/.odbc.ini and make sure the right path and filename is used for your installation.

A data source is a section (enclosed in square parenthesis), and the attributes for a data source are given within this section. The most important attribute to iODBC for each datasource is the Driver attribute. This must point to the shared library for the ODBC driver associated with the data source.

As example, the OpenLink ODBC drivers have a number of attributes which can be set for a data source. Here is a description (with ODBC connect string tags between parenthesis):

    The hostname where the database resides (HOST).

    The type of server (see oplrqb.ini on the server, SVT).

    Server-specific extra options. See OpenLink server documentation for agents which can use this.

    The database to use (DATABASE).

    Connect options for the database (OPTIONS).

    The name of the user (a password cannot be specified in the UDBCINI file, UID/PWD).

    A Yes/No value in order to make the connection read-only (READONLY=Y/N).

    The number of records that are transferred in a single call to the server. 
    Default is 5; maximum is 99, minimum is 1 (FBS=value).

    The protocol to use. Leave set to TCP for this release.

Apart from these data source-specific settings, you may add a section called [Communications], which you may use to tune our driver further:

    The time the client application will wait for the database agent to finish the request (default is 60 seconds).

    The time the client application will wait for the request broker to accept of reject a database connection 
    Default is 30 seconds.

    RPC send buffer size. A value of 0 (the default) will cause the application to use system-dependent defaults.

    RPC receive buffer size. A value of 0 (the default) will cause the application to use system-dependent defaults.

    If set, the name of a file to which debugging output from the driver should be directed.

iODBC driver manager platform availability

The iODBC driver manager has been ported to following Unix platforms:

| os              | version       | processor                 |
| --------------- | ------------- | ------------------------- |
| BSDi BSD/OS     | 2.x           | x86                       |
| DEC Unix(OSF/1) | 3.x - 5.x     | DEC Alpha                 |
| DG/UX           | 5.x           | Aviion                    |
| FreeBSD         | 2.x - 9.x     | x86                       |
| HP/UX           | 9.x - 11.x    | HP9000 s700/s800          |
| HP/UX           | 9.x           | HP9000 s300/s400          |
| IBM AIX         | 3.x - 5.x     | IBM RS6000, PowerPC       |
| Linux ELF       | 1.x,  2.x     | x86, Itanium, PowerPC     |
| Mac OS X        | 10.x          | PowerPC                   |
| Max/OS SVR4     | 1.x           | Concurrent Maxion 9200 MP |
| NCR SVR4        | 3.x           | NCR 3435                  |
| OpenVMS         | 6.x           | DEC Alpha                 |
| SCO OpenServer  | 5.x           | x86                       |
| SGI Irix SVR4   | 5.x, 6.x      | IP12 MIPS, IP22 MIPS      |
| SunOS           | 4.1.x         | Sun Sparc                 |
| Sun Solaris     | 2.x           | Sun Sparc, PCx86          |
| UnixWare SVR4.2 | 1.x, 2.x      | x86                       |
| Windows NT      | 4.x           | x86                       |

As the iODBC driver manager uses autoconf/automake/libtool it should be portable to most modern UNIX platforms out of the box. However if you do need to make changes to the code or the configuration files, we would appreciate you share your changes with the rest of the internet community by mailing your patches to so we can include them for the next build.

Porting of iODBC driver manager to some non-UNIX operating systems such as Windows family(3.x, 95, NT), OS/2 and Mac Classic is supported but has not been compiled and tested recently. Of cause, you need to supply a make/build file and a short LibMain for creating the iodbc.dll.

How to build iODBC driver manager:

Mac OS X users should read the separate README_MACOSX document for more detail of porting on this platform. Otherwise:

step 1. Run configure to adjust to target platform
step 2. Run make
step 3. Run make install

The configure program will examine your system for various compiler flags, system options etc. In some cases extra flags need to be added for the C compiler to work properly.

E.g. on HP systems you may need:

$ CFLAGS="-Ae -O" ./configure --prefix=/usr/local ..........

File Hierarchy

Note that the path of the system wide odbc.ini file is calculated as follows (based on flags to ./configure):

no --prefix                     default is /etc/odbc.ini
--prefix=/usr                   /etc/odbc.ini
--prefix=/xxx/yyy               /xxx/yyy/etc/odbc.ini
--sysconfdir=/xxx/yyy           /xxx/yyy/odbc.ini
--with-iodbc-inidir=/xxx/yyy    /xxx/yyy/odbc.ini

If the --with-layout= option is set, then the prefix and sysconfdir parameters will be changed accordingly. Currently, this parameter understands values of gentoo**, redhat, gnu, debian or opt (with everything going into /opt/iodbc/). If both are specified, a --prefix argument will overrule a --with-layout.


    $ ./configure --prefix=/usr/local --with-iodbc-inidir=/etc
    $ make
    $ su
    # make install


Driver manager and drivers use odbc.ini file or connection string when establishing a data source connection. On Windows, odbc.ini is located in Windows directory.

On UNIX, the iODBC driver manager looks for the odbc.ini file in the following sequence:

  1. check environment variable ODBCINI

  2. check $HOME/.odbc.ini

  3. check home in /etc/passwd and try .odbc.ini in there

  4. system-wide odbc.ini (settable at configuration time)

Item 1 is the easiest as most drivers will also look at this variable.

The format of odbc.ini( or ~/.odbc.ini ) is defined as:

odbc.ini            ::= data_source_list

data_source_list    ::= /* empty */
                     | data_source '\n' data_source_list

data_source         ::= '[' data_source_name ']' '\n' data_source_desc

data_source_name    ::= 'default' | [A-Za-z]*[A-Za-z0-9_]*

data_source_desc    ::= /* empty */
                     | attrib_desc '\n' data_source_desc

addrib_desc         ::= Attrib '=' attrib_value

Attrib              ::= 'Driver' | 'PID' | 'UID' | driver_def_attrib

driver_def_attrib   ::= [A-Za-z]*[A-Za-z0-9_]*

An example of an odbc.ini file:

;  odbc.ini
[ODBC Data Sources]
Myodbc          = Myodbc
Sample          = OpenLink Generic ODBC Driver
Virtuoso        = Virtuoso

TraceFile       = /tmp/odbc.trace
Trace           = 0        ; set to 1 to enable tracing

Driver          = /usr/local/openlink/lib/
Description     = Sample OpenLink DSN
Host            = localhost
UserName        = openlink
Password        = xxxx
ServerType      = Oracle 8.1.x
Database        =
FetchBufferSize = 99
ReadOnly        = no

Driver          = /usr/local/virtuoso/lib/
Address         = localhost:1112
Database        = Demo

Driver          = /usr/lib/
HOST            = localhost

Driver          = /usr/local/openlink/lib/


The iODBC driver manager traces driver's ODBC call invoked by the driver manager. Default tracing file is ./odbc.log. Tracing option (i.e. on/off or optional tracing file name) can be set in odbc.ini file under the [ODBC] heading as:

TraceFile = <optional_trace_file>
Trace = ON | On | on | 1 | OFF | Off | off | 0

If <optional_trace_file> is stderr or stdout, i.e.

TraceFile = stderr


TraceFile = stdout

the tracing message will go to the terminal screen (if it is available).

Further Information Sources:

iODBC Website containing binaries, sources and documentation.

iODBC Project page on GitHub containing source archives, GIT tree, issues forum.

iODBC Project page on Sourceforge containing source archives, GIT tree, mailing lists, forums, bug reports.

OpenLink Software Website containing free trials and support for OpenLink's ODBC drivers.

Microsoft ODBC Documentation containing the ODBC API Reference Guide.


An open-source ODBC driver manager and SDK that facilitates the development of database-independent applications on linux, freebsd, unix and MacOS X platforms.




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