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SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Guide to SQL: Reference
The Informix® Guide to SQL: Reference contains the reference information for the system catalog tables, data types, and environment variables of the HCL Informix dialect of the SQL language, as implemented in HCL Informix. These topics also include information about the stores_demo, sales_demo, and superstore_demo databases that are included with HCL Informix.
Environment variables
Various environment variables affect the functionality of your HCL Informix® products. You can set environment variables that identify your terminal, specify the location of your software and define other parameters.
Using environment variables on Windows™
Where to set environment variables on Windows™

SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
- Guide to SQL: Syntax
- Guide to SQL: Reference
  The Informix® Guide to SQL: Reference contains the reference information for the system catalog tables, data types, and environment variables of the HCL Informix dialect of the SQL language, as implemented in HCL Informix. These topics also include information about the stores_demo, sales_demo, and superstore_demo databases that are included with HCL Informix.
  - System catalog tables
    The system catalog consists of tables and views that describe the structure of the database. Sometimes called the data dictionary, these table objects contain everything that the database knows about itself. Each system catalog table contains information about specific elements in the database. Each database has its own system catalog.
  - Data types
    Every column in a table in a database is assigned a data type. The data type precisely defines the kinds of values that you can store in that column.
  - Environment variables
    Various environment variables affect the functionality of your HCL Informix® products. You can set environment variables that identify your terminal, specify the location of your software and define other parameters.
    - Types of environment variables
    - Limitations on environment variables
    - Using environment variables on UNIX™
      You can set, unset, modify, and view environment variables. If you already use any HCL Informix® products, some or all of the appropriate environment variables might be set.
    - Using environment variables on Windows™
    - Environment variables in Informix® products
      The topics that follow discuss (in alphabetic order) environment variables that HCL Informix® database server products and their utilities use.
  - Appendixes
- Guide to SQL: Tutorial
  The Informix® Guide to SQL: Tutorial shows how to use basic and advanced structured query language (SQL) to access and manipulate the data in your databases. It discusses the data manipulation language (DML) statements as well as triggers and stored procedure language (SPL) routines, which DML statements often use.

Where to set environment variables on Windows™

You can set environment variables in several places on Windows™, depending on which HCL Informix® application you use.

Environment variables can be set in several ways, as described in Setting environment variables on Windows.

The SET ENVIRONMENT statement of SQL can set certain routine-specific environment options. For more information, see the description of SET ENVIRONMENT in the Informix® Guide to SQL: Syntax.

To use client applications such as Informix® ESQL/C or the Schema Tools on Windows™ environment, use the Setnet32 utility to set environment variables. For information about the Setnet32 utility, see the Informix® Client Products Installation Guide for your operating system.

In Informix® ESQL/C, you can set supported environment variables within an application with the ifx_putenv() function and retrieve values with the ifx_getenv() function, if your Windows™ system supports them. For more information about ifx_putenv() and ifx_getenv(), see the Informix® ESQL/C Programmer's Manual.