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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™
Setting environment variables on Windows™
Using dbservername.cmd to initialize a command-prompt environment
Each time that you open a Windows™ command prompt, it acts as an independent environment. Therefore, environment variables that you set within it are valid only for that particular command-prompt instance.

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™
      - Where to set environment variables on Windows™
      - Setting environment variables on Windows™
        Using the system applet to change environment variables
        The System applet provides a graphical interface to create, modify, and delete system-wide and user-specific variables. Environment variables that are set with the System applet are visible to all command-prompt sessions.
        Using the command prompt to change environment variables
        You can change the setting of an environment variable at a command prompt.
        Using dbservername.cmd to initialize a command-prompt environment
        Each time that you open a Windows™ command prompt, it acts as an independent environment. Therefore, environment variables that you set within it are valid only for that particular command-prompt instance.
      - Rules of precedence for Windows™ environment variables
    - 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.

Using dbservername.cmd to initialize a command-prompt environment

Each time that you open a Windows™ command prompt, it acts as an independent environment. Therefore, environment variables that you set within it are valid only for that particular command-prompt instance.

About this task

For example, if you open one command window and set the variable, INFORMIXDIR, and then open another command window and type set to check your environment, you will find that INFORMIXDIR is not set in the new command-prompt session.

The database server installation program creates a batch file that you can use to configure command-prompt utilities, ensuring that your command-prompt environment is initialized correctly each time that you run a command-prompt session. The batch file, dbservername.cmd, is located in %INFORMIXDIR%, and is a plain text file that you can modify with any text editor. If you have more than one database server installed in %INFORMIXDIR%, there will be more than one batch file with the .cmd extension, each bearing the name of the database server with which it is associated.

To run dbservername.cmd from a command prompt, type dbservername or configure a command prompt so that it runs dbservername.cmd automatically at start.