Home
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 DataBlade® 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.
Creating extensions
You can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in Informix® databases.
DataBlade® API Programmer's Guide
The Informix® DataBlade® API Programmer's Guide describes information about the DataBlade API, the C-language application programming interface (API) provided with HCL Informix.
Data manipulation
Smart large objects
The smart-large-object interface
The smart-large-object interface contains a set of functions and data types to provide access to smart large objects.
Smart-large-object data type structures
The smart-large-object interface provides data type structures that store information about a smart large object.

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 DataBlade® 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.
- Informix® extensions and DataBlade® modules
  These topics describe how to use built-in database extensions and separately installed DataBlade® modules.
- Creating extensions
  You can create user-defined data types, routines, access methods, and other database objects to suit your needs. You can use application programming interfaces to write user-defined routines and applications that access data in Informix® databases.
  - DataBlade® API Programmer's Guide
    The Informix® DataBlade® API Programmer's Guide describes information about the DataBlade API, the C-language application programming interface (API) provided with HCL Informix.
    - DataBlade® API overview
    - Data manipulation
      - Numeric data types
        This section describes these numeric data types and the functions that the DataBlade® API supports to process numeric data.
      - Date and time data types
        This section describes the date and time data types and the functions that the DataBlade® API supports to process date and time data.
      - Complex data types
        This section describes the complex data types and the functions that the DataBlade® API supports to process collection and row-type data.
      - Smart large objects
        Smart large objects
        Storing a smart large object in a database
        To store a smart large object in a database, you must save its LO handle in a column. This section describes the valid data types to hold an LO handle and how to access a smart large object.
        The smart-large-object interface
        The smart-large-object interface contains a set of functions and data types to provide access to smart large objects.
        Smart-large-object data type structures
        The smart-large-object interface provides data type structures that store information about a smart large object.
        Lo-specification structure
        The LO-specification structure, MI_LO_SPEC, defines the storage characteristics for an existing or a new smart large object. The storage characteristics provide information about features of the smart large object and how to store it on disk.
        LO handle
        A LO handle, MI_LO_HANDLE, serves as a reference to a smart large object. It is analogous to the file name of an operating-system file in that it is a unique identifier of a smart large object. The LO handle contains encoded information about the smart large object, such as its physical disk location and other security-related information. After a smart large object is created, an associated LO handle is a valid reference for the life of that smart large object.
        Lo file descriptor
        The LO file descriptor, MI_LO_FD, is a reference to an open smart large object. An LO file descriptor is similar to a file descriptor for an operating-system file. It is an integer number that serves as a transient descriptor for performing I/O on the data of the smart large object.
        Lo-status structure
        The LO-status structure, MI_LO_STAT, contains the status information for an existing smart large object.
        Smart-large-object functions
        Creating a smart large object
        Accessing a smart large object
        Modify a smart large object
        After you have an LO file descriptor for an open smart large object, you can modify the smart large object by updating the smart large object or by altering some storage characteristics of the smart large object.
        Obtaining status information for a smart large object
        Delete a smart large object
        Convert a smart large object to a file or buffer
        The DataBlade® API provides support for the conversion of a smart large object to or from either an operating-system file or a user-defined buffer.
        Convert an LO handle between binary and text
        The DataBlade® API library provides functions that convert between the binary (internal) representation of an LO handle and its text (string) representation.
        Transfer an LO handle between computers (Server)
        For an LO handle to be portable when transferred across different computer architectures, the DataBlade® API provides functions to handle type alignment and byte order.
        Using byte-range locking
        By default, the database server uses whole lock-all locks when it needs to lock a smart large object. Lock-all locks are an all or nothing lock; that is, they lock the entire smart large object.
        Pass a NULL connection (Server)
        Many functions in the smart-large-object interface take a connection descriptor as a parameter. However, many of the functions also accept a NULL-valued pointer as a connection descriptor.
    - Database access
    - Create user-defined routines
    - Appendix
      This section contains additional reference information.
  - DataBlade® API Function Reference
    The Informix® DataBlade® API Function Reference describes the DataBlade API functions and the subset of Informix ESQL/C functions that the DataBlade API supports.
  - DataBlade® Developers Kit
    The DataBlade® Developers Kit (DBDK) guides contain information about the tools you can use to develop and package DataBlade modules, which extend the functionality of HCL Informix® databases.
  - J/Foundation Developer's Guide
    The J/Foundation Developer's Guide describes how to write user-defined routines (UDRs) in the Java™ programming language for Informix®.
  - R-Tree Index User's Guide
    The Informix® R-Tree Index User's Guide describes the HCL Informix R-tree secondary access method and how to access and use its components.
  - User-Defined Routines and Data Types Developer's Guide
    The Informix® User-Defined Routines and Data Types Developer's Guide describes how to define new data types and enable user-defined routines (UDRs) to extend HCL Informix.
  - Virtual-Table Interface Guide
    The Informix® Virtual-Table Interface Programmer's Guide explains how to create a primary access method with the Virtual-Table Interface (VTI) so that users have a single SQL interface to HCL Informix tables and to data that does not conform to the storage scheme of HCL Informix.
  - Virtual-Index Interface Guide
    The Informix® Virtual-Index Interface Programmer's Guide explains how to create a secondary access method with the Virtual-Index Interface (VII) to extend the built-in indexing schemes of HCL Informix typically with a DataBlade® module.

Smart-large-object data type structures

The smart-large-object interface provides data type structures that store information about a smart large object.

The following table summarizes the data type structures of the smart-large-object interface.

Table 1. Data types of the smart-large-object interface
Smart-large-object data type structure	Data type	Description
The LO-specification structure	MI_LO_SPEC	Holds storage characteristics for a smart large object
The LO handle	MI_LO_HANDLE	Identifies the location of the smart large object; analogous to the file name of an operating-system file
The LO file descriptor	MI_LO_FD	Identifies an open smart large object; analogous to the file descriptor of an operating-system file
The LO-status structure	MI_LO_STAT	Holds status information about a smart large object

These structures are all opaque to a DataBlade® API module; that is, you do not access their fields directly but instead use accessor functions that the smart-large-object interface provides.