Welcome
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Informix® ODBC Driver Guide
The Informix® ODBC Driver Programmer's Manual serves as a user guide and reference for HCL Informix ODBC Driver, which is the Informix implementation of the Microsoft™ Open Database Connectivity (ODBC) interface, Version 3.0.
Client functions
These topics describe the HCL Informix® ODBC Driver client functions. Use these functions to access and manipulate smart large objects and rows and collections.
Functions for rows and collections
This section describes each client function that HCL Informix® ODBC Driver provides for rows and collections.
The ifx_rc_isnull() function
The ifx_rc_isnull() function returns a value that indicates whether a row or collection is null.

HCL Informix® V15.0.0 documentation
Welcome to the documentation for HCL Informix® 15.0.0 and related client tools and products.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
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 HCL® Informix® Change Data Capture API Programmer's Guide describes how to program applications to process changed data from HCL Informix databases using the HCL Informix Change Data Capture API.
- Embedded SQLJ for HCL Informix®
  The HCL® Informix® Embedded SQLJ User's Guide contains information about using HCL Informix Embedded SQLJ.
- ESQL/C Guide
  The HCL® Informix® Enterprise Replication Guide explains how to use , 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 HCL® Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in HCL Informix products.
- Informix GLS 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 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 HCL Informix ODBC Driver, which is the Informix implementation of the Microsoft™ Open Database Connectivity (ODBC) interface, Version 3.0.
  - Overview of HCL Informix® ODBC Driver
    These topics introduce the HCL Informix® ODBC Driver and describe its advantages and architecture. The topics also describe conformance, isolation and lock levels, libraries, and environment variables.
  - Configure data sources
    These topics explain how to configure a data source (DSN) on UNIX™ and Windows™ for HCL Informix® ODBC Driver.
  - Data types
    These topics contain information about the data types that are supported by HCL Informix® ODBC Driver.
  - Smart large objects
    These topics describe how to store, create, and access a smart large object; how to transfer smart-large-object data; how to retrieve the status of a smart large object; and how to read or write a smart large object to or from a file.
  - Rows and collections
    Rows and collections are composite values that consist of one or more elements.
  - Client functions
    These topics describe the HCL Informix® ODBC Driver client functions. Use these functions to access and manipulate smart large objects and rows and collections.
    - Call a client function
      This section describes the syntax of client functions, their input/output arguments, return values, and SQL_BIGINT.
    - Functions for smart large objects
      This section describes each client function that the driver provides for smart large objects.
    - Functions for rows and collections
      This section describes each client function that HCL Informix® ODBC Driver provides for rows and collections.
      - The ifx_rc_count() function
        The ifx_rc_count() function returns the number of elements or fields that are in a row or collection.
      - The ifx_rc_create() function
      - The ifx_rc_delete() function
        The ifx_rc_delete() function deletes an element from a collection.
      - The ifx_rc_describe() function
        The ifx_rc_describe() function returns descriptive information about the data type for a row or collection or for an element that is in a row or collection.
      - The ifx_rc_fetch() function
        The ifx_rc_fetch() function retrieves the value of an element that is in a row or collection.
      - The ifx_rc_free() function
        The ifx_rc_free() function frees a row or collection handle.
      - The ifx_rc_insert() function
        The ifx_rc_insert() function inserts a new element into a collection.
      - The ifx_rc_isnull() function
        The ifx_rc_isnull() function returns a value that indicates whether a row or collection is null.
      - The ifx_rc_setnull() function
        The ifx_rc_setnull() function sets a row or collection to null.
      - The ifx_rc_typespec() function
        The ifx_rc_typespec() function returns the type specification for a row or collection.
      - The ifx_rc_update() function
        The ifx_rc_update() function updates the value for an element that is in a row or collection.
  - Application tracking in ODBC
    Set the CLIENT_LABEL environment variable in CSDK 4.50.xC4 onwards to assign a character string to ODBC client session and identify that character string on the database server. You can use this variable to distinguish one database session from the other.
  - Improve application performance
    These topics suggest ways to improve performance of HCL Informix® ODBC Driver applications.
  - Error messages
    These topics describe the HCL Informix® ODBC Driver error messages.
  - Unicode
    These topics provide a brief overview of the Unicode standard and shows how it is used within ODBC applications.
  - ODBC Smart trigger
- Informix .NET Core Provider
  Starting with CSDK 4.50.xC4, Informix .NET Core Provider built with .NET Core SDK/Runtime v3.1 is shipped for Windows x64 and Linux x86_64 platforms.
- Informix® .NET EF Core Provider Guide
- HCL Informix 4GL
  This topic provides a link to the Informix 4GL documentation.
- Informix® JDBC Driver Guide
  The HCL® Informix® JDBC Driver Programmer's Guide describes how to install, load, and use HCL 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 HCL Informix OLE DB Provider Programmer's Guide describes the software requirements for using HCL 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.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
Extending Informix®
Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix includes many built-in extensions that are fully integrated in the database server. Informix also provides modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.

The ifx_rc_isnull() function

The ifx_rc_isnull() function returns a value that indicates whether a row or collection is null.

Syntax

ifx_rc_isnull(nullflag, rchandle)

Arguments

The function accepts the following arguments.


Argument	Type	Use	Description
nullflag	SQL_SMALLINT	Output	Flag that indicates whether a row or collection is null. The possible values are: TRUE FALSE
rchandle	HINFX_RC	Input	Handle for a row or collection buffer

Usage

The ifx_rc_isnull() function returns a value that indicates whether a row or collection is null.