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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.
Data structures for smart large objects
The LO-specification structure
Before you create a new smart large object, you must allocate an LO-specification structure with the ifx_lo_def_create_spec() function.
The ifx_lo_create_spec_t structure
The LO-specification structure, ifx_lo_create_spec_t, stores the storage characteristics for a smart large object in the Informix® ESQL/C program.
Disk-storage information
The LO-specification structure stores disk-storage information, which helps the database server determine how to store the smart large object most efficiently on disk.

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
        Declare a host variable
        The LO-specification structure
        Before you create a new smart large object, you must allocate an LO-specification structure with the ifx_lo_def_create_spec() function.
        The ifx_lo_create_spec_t structure
        The LO-specification structure, ifx_lo_create_spec_t, stores the storage characteristics for a smart large object in the Informix® ESQL/C program.
        Disk-storage information
        The LO-specification structure stores disk-storage information, which helps the database server determine how to store the smart large object most efficiently on disk.
        Create-time flags
        The LO-specification structure stores create-time flags, which tell the database server what options to assign to the smart large object.
        ESQL/C functions that use the LO-specification structure
        Obtain storage characteristics
        Deallocate the LO-specification structure
        After you are finished with an LO-specification structure, deallocate the resources assigned to it with the ifx_lo_spec_free() function. When the resources are freed, they can be reallocated to other structures that your program needs.
        The LO-pointer structure
        The LO file descriptor
        The LO file descriptor is an integer value that identifies an open smart large object.
      - Creating a smart large object
      - Accessing a smart large object
      - 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.

Disk-storage information

The LO-specification structure stores disk-storage information, which helps the database server determine how to store the smart large object most efficiently on disk.

The following table shows the disk-storage information along with the corresponding Informix® ESQL/C access functions.

Table 1. Disk-storage information in the LO-specification structure
Disk-storage information	Description	ESQL/C accessor functions
Estimated number of bytes	An estimate of the final size, in bytes, of the smart large object. The database server uses this value to determine the extents in which to store the smart large object. This value provides optimization information. If the value is grossly incorrect, it does not cause incorrect behavior. However, it does mean that the database server might not necessarily choose optimal extent sizes for the smart large object.	ifx_lo_specget_estbytes() ifx_lo_specset_estbytes()
Maximum number of bytes	The maximum size, in bytes, for the smart large object. The database server does not allow the smart large object to grow beyond this size.	ifx_lo_specget_maxbytes() ifx_lo_specset_maxbytes()
Allocation extent size	The allocation extent size is specified in kilobytes. Optimally, the allocation extent is the single extent in a chunk that holds all the data for the smart large object. The database server performs storage allocations for smart large objects in increments of the allocation extent size. It tries to allocate an allocation extent as a single extent in a chunk. However, if no single extent is large enough, the database server must use multiple extents as necessary to satisfy the request.	ifx_lo_sepcget_extsz(), ifx_lo_specset_extsz()
Name of the sbspace	The name of the sbspace that contains the smart large object. The sbspace name can be at most 18 characters long. This name must be null terminated.	ifx_lo_specget_sbspace() ifx_lo_specset_sbspace()

For most applications, it is recommended that you use the values for the disk-storage information that the database server determines.