INFORMIX-ESQL/C Programmer's Manual Introduction

This manual explains how to use INFORMIX-ESQL/C, the Informix implementation of embedded Structured Query Language (SQL) for C, to create client applications with database-management capabilities. This manual is a complete guide to the features of ESQL/C that enable you to interact with the database server, access databases, manipulate the data in your program, and check for errors.

This manual progresses from general topics to more advanced programming techniques and examples.

This manual is written primarily for C programmers who want to embed SQL statements in their programs to access Informix databases.

This manual assumes that you have the following background:

• A working knowledge of your computer, your operating system, and the utilities that your operating system provides
• Some experience working with relational or object-relational databases, or exposure to relational database concepts
• C language programming

The following users might also be interested in some of the topics in this book:

• Database server administrators
• Performance engineers

If you have limited experience with relational databases, SQL, or your operating system, refer to the Getting Started manual for your database server for a list of supplementary titles.

This manual assumes that you are using Informix ODBC Driver, Version 3.3, on either a UNIX or a Windows NT, Windows 95, or a Windows 98 platform.

In places where this manual presents database server-specific information, this information applies to one of the following database servers:

• Informix Dynamic Server
• Informix Dynamic Server with Advanced Decision Support and Extended Parallel Options
• Informix Dynamic Server with Universal Data Option
• Informix Dynamic Server, Workgroup Edition
• INFORMIX-SE

If you are using a database server that is not listed here, see your release notes for information about client behavior on your database server.

Informix products can support many languages, cultures, and code sets. All culture-specific information is brought together in a single environment, called a GLS (Global Language Support) locale.

The examples in this manual are written with the assumption that you are using the default locale, en_us.8859-1. This locale supports U.S. English format conventions for dates, times, and currency. In addition, this locale supports the ISO 8859-1 code set, which includes the ASCII code set plus many 8-bit characters such as é, è, and ñ.

If you plan to use nondefault characters in your data or your SQL identifiers, or if you want to conform to the nondefault collation rules of character data, you need to specify the appropriate nondefault locale.

For instructions on how to specify a nondefault locale, additional syntax, and other considerations related to GLS locales, see the Informix Guide to GLS Functionality.

The DB-Access utility, which is provided with your Informix database server products, includes one or more demonstration databases that contain information about a fictitious wholesale sporting-goods distributor. You can create and populate these demonstration databases with command files that are included with the database server.

Many examples in Informix manuals are based on these databases. For a complete explanation of how to create and populate the demonstration databases, refer to your DB-Access User Manual. For a description of the demonstration databases and their contents, see your Informix Guide to SQL: Reference.

The scripts that you use to install the demonstration databases reside in the $INFORMIXDIR/bin directory on UNIX and in the %INFORMIXDIR%\bin directory on Windows.

For additional information about INFORMIX-ESQL/C and the demonstration database, see Appendix A, The Demonstration Database.