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Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
GLS User's Guide
The Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in Informix products.
Informix® ESQL/C features
These topics explain how the GLS feature affects Informix® ESQL/C, an SQL application programming interface (API).
Handle code-set conversion
When the client and database code sets differ, the Informix® ESQL/C client application performs code-set conversion on character data.
The DESCRIBE statement
The sqlda structure is a dynamic-management structure that contains information about columns in dynamic SQL statements. The DESCRIBE...INTO statement uses the sqlda structure to return information about the columns in the select list of the Projection clause of a SELECT statement.

Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
- Change Data Capture API Programmer's Guide
  The Informix® Change Data Capture API Programmer's Guide describes how to program applications to process changed data from HCL Informix databases using the Informix Change Data Capture API.
- Embedded SQLJ for HCL Informix®
  The Informix® Embedded SQLJ User's Guide contains information about using Informix Embedded SQLJ.
- ESQL/C Guide
  The Informix® ESQL/C Programmer's Manual explains how to use Informix ESQL/C, the Informix implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
- GLS User's Guide
  The Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in Informix products.
  - GLS fundamentals
    The Global Language Support (GLS) feature lets Informix® products handle different languages, cultural conventions, and code sets for Asian, African, European, Latin American, and Middle Eastern countries.
  - GLS environment variables
    HCL Informix® products establish the client, database, and server locales with information from GLS-related environment variables and from data that is stored in the database.
  - SQL features
    These topics explain how the GLS feature affects the Informix® implementation of SQL.
  - Database server features
    These topics describe how the GLS feature affects the database server.
  - General SQL API features (ESQL/C)
    These topics explain how the GLS feature affects applications that you develop with the Informix® Client Software Development Kit.
  - Informix® ESQL/C features
    These topics explain how the GLS feature affects Informix® ESQL/C, an SQL application programming interface (API).
    - Handle non-ASCII characters
      The Informix® ESQL/C processors obtain the code set for use in Informix ESQL/C source files from the client locale.
    - Define variables for locale-sensitive data
      The SQL data types NCHAR and NVARCHAR support locale-specific data, in the sense that the database server uses localized collation (if the locale defines localized collation), rather than code set order, for sorting data strings of these types.
    - Enhanced ESQL/C library functions
      Informix® SQL API products support locale-specific enhancements to the Informix ESQL/C library functions.
    - Handle code-set conversion
      When the client and database code sets differ, the Informix® ESQL/C client application performs code-set conversion on character data.
      - Writing TEXT values
        Informix® ESQL/C uses the loc_t locator structure to read simple large objects from and write simple large objects to the database server.
      - The DESCRIBE statement
        The sqlda structure is a dynamic-management structure that contains information about columns in dynamic SQL statements. The DESCRIBE...INTO statement uses the sqlda structure to return information about the columns in the select list of the Projection clause of a SELECT statement.
        The sqldata field
        To hold the column data, the client application must allocate a buffer and set sqldata to point to this buffer. If your client application might perform code-set conversion, it must allocate sufficient storage to handle the increase in the size of the column data that might occur.
        The sqlname field
        The sqlname field contains the name of the column.
    - The TRIM function
      When you dynamically execute a SELECT statement, the DESCRIBE statement can return information about the columns in the select list of the Projection clause at run time. DESCRIBE returns the data type of a select-list column in the appropriate field of the dynamic-management structure that you use.
  - Appendix
    This section contains additional reference information.
- API
  The Informix® GLS API Programmer's Guide describes the global language support (GLS) application programming interface (API) available in Informix ESQL/C and HCL Informix DataBlade® modules.
- Informix® Object Interface for C++ Guide
  The Informix® Object Interface for C++ Programmer's Guide describes how to develop HCL Informix client applications by using the object-oriented C++ programming language.
- Informix® ODBC Driver Guide
  The Informix® ODBC Driver Programmer's Manual serves as a user guide and reference for Informix ODBC Driver, which is the Informix implementation of the Microsoft™ Open Database Connectivity (ODBC) interface, Version 3.0.
- .NET provider options
  The Data Server Provider for .NET DB2® provider option is the preferred Informix® provider for developing new applications.
- Informix® JDBC Driver Guide
  The Informix® JDBC Driver Programmer's Guide describes how to install, load, and use Informix JDBC Driver to connect to the Informix database from within a Java™ application or applet.
- Informix International Language Supplement (ILS) User Guide
  These topics include information about the translated user interface files for Informix® UNIX™ products, locales, and code set conversion tables
- Informix® OLE DB Provider Guide
  The Informix® OLE DB Provider Programmer's Guide describes the software requirements for using Informix OLE DB Provider, show how to install and configure the provider for your use, and explain how to use Informix OLE DB Provider to enable client applications, such as ActiveX Data Object (ADO) applications and web pages, to access data on the Informix server.

The DESCRIBE statement

The sqlda structure is a dynamic-management structure that contains information about columns in dynamic SQL statements. The DESCRIBE...INTO statement uses the sqlda structure to return information about the columns in the select list of the Projection clause of a SELECT statement.

It sets the sqlvar field of an sqlda structure to point to a sequence of partially filled sqlvar_struct structures. Each structure describes a single select-list column.

Each sqlvar_struct structure contains character data for the column name and the column data. When the Informix® ESQL/C client application fills this structure, the column name and the column data are in the client code set. When the database server fills this structure and executes a DESCRIBE...INTO statement, this character data is in the database code set.

When the client application performs code-set conversion between the client and database code sets, the number of bytes that is required to store the column name and column data in the client code set might not equal the number that is required to store this same information in the database code set. Therefore, the size of the character data in sqlvar_struct might increase or decrease during code-set conversion. To handle this possible difference in size, the client application must ensure that it correctly handles the character data in the sqlvar_struct structure.