Informix ODBC Setup

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Using CLI to Connect to Informix Databases Through ODBCby James Edmiston

Introduction

There are many third-party tools on the market for developing client applications and performing query

and reporting against Informix databases. In this article we will discuss how to enable third-party tools to

access Informix databases through ODBC by installing and configuring Informix-CLI. Although CLI is the

client connectivity tool for both a UNIX client and a Windows client, we will only discuss setting up

ODBC for Microsoft Windows environments.

Application development tools like PowerBuilder and Visual Basic enable a developer to create client

applications to access RDBMS databases. Products like BrioQuery give the user a front-end tool to report

on their data located on a database server. You may even have a need to use Microsoft Access database to

link to an Informix database.

The connection from a Windows client to an Informix database server is achieved by utilizing the

Microsoft Open Database Connectivity (ODBC) standard. ODBC is an API specification that enables

access to multiple DBMS's using SQL. ODBC enforces a standard that gives client applications

interoperability across database platforms.

An ODBC enabled application gains access to a database through the use of an ODBC driver. Each

DBMS requires a different driver. The Informix ODBC drivers are bundled in a suite of client connectivity

products.

Informix Products

rmix ODBC Setup http://www.synametrics.com/ifmxODBC.htm

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Informix provides a suite of connectivity products that are used to enable Microsoft Windows' clients to

access Informix servers. The two main products are Informix-CLI and Informix Connect. In the past, each

of these products was shipped as a separate installation CD. As of this year, these products are bundled

together on one installation CD called Informix Client Software Developers Kit for Microsoft

Windows Environments, or Informix Client SDK.

The Client SDK contains much more than CLI and Connect. It includes programmer API's for C++,

ESQL/C and Java. It also contains the latest Informix ODBC drivers and two versions of the ODBC

Driver Manager. The remainder of this article will focus on installing Informix-CLI and the related

components, and configuring the Windows client to use the latest ODBC driver to connect to an Informix

database server.

There are several options to choose from when installing SDK. Early in the installation process, there is a

choice of "Typical", "Compact" or "Custom" install. If you choose "Custom" you can see all of the

components of the SDK. A "Typical" install will provide the components necessary to establish an ODBC

setup.

Following is a brief description of some of the key products from the installation CD:

Informix-CLI is the Informix implementation of the Microsoft ODBC standard. Informix-CLI is a call

level interface, or connectivity tool that enables applications to dynamically access Informix database

servers. CLI is composed of API libraries, a version of the driver manager and a version of the ODBC

driver. CLI version 2.8 is delivered in Informix-Client SDK version 2.01 and contains an ODBC driver

(version 2.8) for Informix.

The Microsoft ODBC Driver Manager (or ODBC DM) is used for configuring an ODBC data source

(more discussion about the ODBC data source later). The driver manager is also known as the data source

administrator and can be found in the Windows control panel. The Driver Manager may already be

installed on the client by another product. There are 2 versions in the component install list on the Client

SDK installation CD. Driver Manager version 2.5 and version 3.0. Refer to theInformix Client Products

Installation Guide for Microsoft Windows Environments for more details on ODBC driver manager.

The Intersolv ODBC Driver is another component bundled in the Client SDK. The Informix ODBC

driver, version 2.8, is automatically installed with Informix CLI version 2.8. The more recent driver, the

Intersolv Data Direct ODBC driver version 3.01, is a separate component in the list of options in the SDKinstall. If you use the version installed with CLI (version 2.8), it is recommended that you use version 2.5

of the ODBC DM. ODBC DM version 3.0 is required if you use the Intersolv Data Direct ODBC driver.

Informix Connect is composed of the runtime versions of the connectivity components. Connect comes

bundled with most of the Informix Windows client products. This product is useful because it can be

deployed on client machines to enable completed applications to connect to Informix databases in the

Windows environment.

Once you have installed the products on the Windows client, you must configure the products using theproper server and database information.

Component Configuration


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The first configuration step is to create a server entry on the Windows client machine, and provide values

for the Informix variables. Informix includes a utility in the connectivity products called "Setnet32". Its

function is to provide the Windows client with the information it needs to connect to the server by

defining the database server, host machine, network protocol and user account information. Setnet32

saves these entries in the Windows registry. A helpful feature of this utility is the ability to save the

configuration to a file and conversely load it from a file. If there are several clients to configure with the

same server information, an initial machine can be configured manually, the configuration saved to a file

and loaded on other client machines.

To use Setnet32 on the Windows client, click on Start, Programs, the Informix program group installed

with SDK, then Setnet32. The first screen that is displayed shows a list of environment variables. Some of

the environment variables are required and some are optional. The majority of the environment variables

on the client are used for CLI function calls and GLS programming. We will focus on two variables used

to establish client/server connectivity.

The Environment tab of Setnet32

In the environment screen, scroll down through the list toward the bottom and check the settings for

INFORMIXDIR and INFORMIXSERVER. The INFORMIXDIR variable is automatically set with the

directory value specified during the software setup and installation. The INFORMIXSERVER variable can

be set manually, or it will automatically be set as a result of entering values in the Server Information tab.

In the Server Information tab, define an entry for the server.


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The Server Information tab of Setnet32

Informix Server - the Informix database server/instance name.

HostName - the name of the host machine where the database server resides.

Protocolname - the network communication protocol.

Service Name - the service name in the services file that corresponds to the listening port.

Options - this is used for defining groups.

After the information has been entered, click on "Make Default Server" and the INFORMIXSERVER

variable in the Environment tab will be set with the value from the from "Informix Server" field. Click on

the "Apply" button to create the entry and click on "OK" when finished. Define as many servers as

needed.

If you are familiar with setting up Informix Dynamic Server for UNIX, you may find these entries are

identical to the information entered in the sqlhosts file. This information is saved in the Windows registry

under a key value - SQLHOSTS. As a result, there is no need to have a sqlhosts file on the Windows

machine. Rather, the INFORMIXSQLHOSTS variable in the Environment tab contains the name of the

client machine name where the registry entries reside.

ODBC Data Source

A Data Source consists of an ODBC driver, a database and the server information. The server information

is the same information defined previously in Setnet32. A Data Source is created using the ODBC Driver

Manager or ODBC Data Source Administrator as discussed previously. The ODBC Data Source


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Administrator is started in Windows by clicking on Start, Settings, Control Panel, and ODBC.

In the initial screen, click on the "Add" button to create a new data source. A list is displayed showing all

of the ODBC drivers installed on the Windows client. From this list you can see the version numbers and

actual file names of the drivers.

Selecting the ODBC driver during data source creation

To reiterate what was previously mentioned, the first Informix ODBC driver in the list above, version

2.80, is automatically installed with the CLI components. The second Informix driver, version 3.01, is a

separate component in the list of options in the SDK install. There are different characteristics associated

with each driver concerning the actual ODBC data source set up. The example below illustrates creating

an ODBC data source using the version 3.01 driver.

"General" tab: Entering the name, description, and database


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during data source creation

In the General tab, enter the data source name, description and database name. The key here is specifying

the exact database name that you are connecting to.

"Connection" tab: The host, service, server and protocol are filled

in from the "default server" specification in Setnet32

In the Connection tab, the default server information is automatically filled in from the server creation in

the Setnet32 utility. If this particular data source needs to connect to a server other than the default,

simply specify the values here. Once the information is entered in the "General" and "Connection" tabs,

click on "OK" and the ODBC data source is complete.

Services File

The final configuration item is adding an entry to the services file on the client machine. This is identical

to the /etc/services file in the UNIX environment. The entry consists of the service name, listening port

number and protocol. On the client, the service name must match the service name specified from theserver entry created in Setnet32. The listening port number must match the number specified on for the

server. The protocol for a tcp/ip network will be "tcp".

The services file for the Windows client is located in the windows home directory. However, the specific

location depends on the operating system. For Windows 95, the file is c:\windows\services. For Windows

NT, c:\winnt\system32\drivers\etc\services. Use an ASCII editor (Notepad) to open the file and insert a

line to identify the service. The format of the service entry is documented at the top of the file.

An example of a services file entry is:

informix1 1526/tcp #Informix server


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Make sure there is a carriage return at the end of the line.

Testing the connection

After the server is defined to the client and the services file entry has been created, the client to server

connection needs to be tested. The ILogin program is provided as part of the product install to help verify

that all of the information is correct for the client to connect to the server. Execute the utility on theWindows client by clicking on the Start, Programs, the Informix program group installed with SDK, then

"ILogin Demo". Enter a valid user-id and password, and ILogin will automatically attempt to connect to

the default server and run a query against the customer table of the stores7 database. This is a useful tool

for trouble shooting the client to server connection.

The database connection defined in the data source needs to be verified using an ODBC-enabled

application. The application references the data source by the Data Source Name (DSN). Refer to the

product documentation for referencing a DSN. Your connectivity setup is complete once you have

established the connection from the application software to the database.

Summary

The first several times I attempted to configure a client with Setnet32 and ODBC, I would experience a

different error. However, by reading documentation, consulting with others, and through trial and error, I

was able to get to the point where I could accomplish the process without any problems. I've included

some of the "gotchas" that I experienced.

2. Informix error -908. Verify the listening port number defined on the server matches the client.

4. Informix error -931. Verify the service file entry matches the service name in the Setnet32 Server

Information tab.

6. Informix errors -951 and -956. These errors indicate the user and/or the host machine does not trust the

client machine. The client machine name may need to be added to the /etc/hosts.equiv and/or the .rhost

file in the user's UNIX home directory on the server machine.

8. You may experience this error during the ODBC setup in the ODBC Data Source Administrator:

The solution to this problem is to explicitly set the INFORMIXDIR and PATH environment variables in

the Environment tab under System Properties in the Control Panel. Create the INFORMIXDIR variableand supply the value of the directory where Informix CLI is installed on the client. Add the Informix

home directory path plus the "\bin" to the beginning of the PATH variable. Set these in the System

Variables section.


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Setting up the client server connectivity may involve more in depth troubleshooting and analysis. Be

prepared to allow time for these activities.

Documentation references.

It is very important to reference the documentation materials that come with the product. In addition to

reading the release notes, there are several manuals that address the steps covered in this article.

2. Informix Client Products Installation Guide for Microsoft Windows Environments, Version 2.0. This

describes how to install and configure the client products addressed in this article.

4. INFORMIX-CLI Programmer's Manual, Version 2.8. This manual is helpful with configuration as well

as the deeper workings of CLI.

6. INTERSOLV DataDirect ODBC Driver User Guide for Informix Database Servers, Version 3.01. This is

an excellent resource for referencing the items covered in this article pertaining to the ODBC driver and

Driver Manager.

James Edmiston is President of Quest Information Systems, Inc. and an Informix Certified Professional.

He serves as Treasurer and Membership Director of the Washington Area Informix Users Group. Visit his

company web site at www.questisinc.com or email him at [email protected].


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Informix ODBC Setup