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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.
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.
What is Informix® ESQL/C?
Smart large objects
A smart large object is a data type that stores large, non-relational data objects such as images, sound clips, documents, graphics, maps and other large objects, and allows you to perform read, write, and seek operations on those objects.
Accessing a smart large object
Select a smart large object

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.
  - What is Informix® ESQL/C?
    - Informix® ESQL/C programming
    - Compile programs
    - Informix® ESQL/C data types
      These topics contain information about the correspondence between SQL and C data types and how to handle data types in the Informix® ESQL/C program.
    - Character and string data types
      These topics explain how to use character data types in the Informix® ESQL/C program.
    - Numeric data types
    - Time data types
      These topics explain how to use date, datetime, and interval data types in the Informix® ESQL/C program.
    - Simple large objects
      A simple large object is a large object that is stored in a blobspace on disk and is not recoverable.
    - Smart large objects
      A smart large object is a data type that stores large, non-relational data objects such as images, sound clips, documents, graphics, maps and other large objects, and allows you to perform read, write, and seek operations on those objects.
      - Data structures for smart large objects
      - Creating a smart large object
      - Accessing a smart large object
        Select a smart large object
        Open a smart large object
        When you open a smart large object, you obtain an LO file descriptor for the smart large object. Through the LO file descriptor, you can access the data of a smart large object as if it were in an operating-system file.
        Delete a smart large object
        A smart large object is not deleted until the current transaction commits and the smart large object is closed, if the application opened the smart large object.
        Modifying a smart large object
        Close a smart large object
        After you have finished the read and write operations on the smart large object, deallocate the resources assigned to it with the ifx_lo_close() function. When the resources are freed, they can be reallocated to other structures that your program needs. In addition, the LO file descriptor can be reallocated to other smart large objects.
      - Obtaining the status of a smart large object
      - Alter a smart-large-object column
      - Migrate simple large objects
      - Read and write smart large objects on an optical disc (UNIX)
      - The ESQL/C API for smart large objects
        The Informix® ESQL/C API for smart large objects allows an application program to access a smart large object much like an operating-system file.
    - Complex data types
      These topics explain how to use collection and row data types in the Informix® ESQL/C program.
    - Opaque data types
      These topics explain how to use the lvarchar, fixed binary, and var binary data types to access an opaque data type from the Informix® ESQL/C program. Use these Informix ESQL/C data types to represent an opaque data type as it is transferred to and from Informix.
  - Database server communication
  - Dynamic SQL
  - Appendixes
    This section contains additional reference information.
- GLS User's Guide
  The Informix® GLS User's Guide describes the Global Language Support (GLS) feature available in Informix products.
- 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.

Select a smart large object

A SELECT statement does not perform the actual output for the smart-large-object data. It does, however, establish a means for the application program to identify a smart large object so that it can then issue Informix® ESQL/C library functions to open, read, write, or perform other operations on the smart large object.

A CLOB or BLOB column in a database table contains the LO-pointer structure for a smart large object. Therefore, when you select a CLOB or BLOB column into an ifx_lo_t host variable, the SELECT statement returns an LO-pointer structure. For this reason, you declare host variables for CLOB and BLOB values as LO-pointer structures.

The following figure shows how the database server transfers the data of a smart large object to the Informix® ESQL/C client application.

begin figure description - This figure is described in the surrounding text. - end figure description — Figure 1. Transferring smart- large-object data from database server to client application

For an example of code that selects a smart large object from a database column, see The create_clob.ec program. For information about how to store a smart large object in the database, see Store a smart large object.