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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® 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.
DataBlade® Developers Kit User's Guide
The HCL Informix® DataBlade® Developers Kit User's Guide describes how to use tools to develop and package DataBlade modules.
Programming DataBlade® module routines in C
This section contains information to help you edit and compile C language source code generated by DataBlade®.
Generated code
Server connection handle
BladeSmith calls mi_open() at the beginning of many of the routines it generates. The mi_open() call obtains a database server connection handle, which is a required argument in many DataBlade® API calls.

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 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.
    - DataBlade® Module Development Overview
      The HCL Informix® DataBlade® module overview serves as an overview of the HCL Informix DataBlade module development process.
    - DataBlade® Developers Kit User's Guide
      The HCL Informix® DataBlade® Developers Kit User's Guide describes how to use tools to develop and package DataBlade modules.
      - Getting started with DataBlade® module development
        This section provides an overview of DataBlade® module development and describes the resources and tools the HCL Informix® database server provides to facilitate development.
      - Design DataBlade® modules
        This section describes the DataBlade® module SQL design issues.
      - Programming guidelines
        Use this section to help you when you write the design specification for your DataBlade® module.
      - Create DataBlade® objects by using BladeSmith
        Use BladeSmith to create DataBlade® modules.
      - Programming DataBlade® module routines in C
        This section contains information to help you edit and compile C language source code generated by DataBlade®.
        Prerequisite tasks
        C programming task overview
        Source files generated by BladeSmith
        When you create objects, BladeSmith generates the source files; some file names are prefixed with the name of the DataBlade® module (indicated by project). By default, BladeSmith creates the source files in the src and src\c subdirectories of the directory that contains the BladeSmith project file.
        Generated code
        Identify the source of generated code
        When BladeSmith generates source code for your DataBlade® module, it uses routines and data structures from various libraries.
        Comments in generated code
        BladeSmith adds comments to the code it generates. Each routine begins with a prologue that describes the purpose of the routine, its arguments, and its return value. Comments throughout the code describe variable declarations and the results of generated C statements and routine calls.
        The MI_FPARAM function argument
        BladeSmith adds an extra argument to all routines it generates: a pointer to an MI_FPARAM structure.
        Server connection handle
        BladeSmith calls mi_open() at the beginning of many of the routines it generates. The mi_open() call obtains a database server connection handle, which is a required argument in many DataBlade® API calls.
        Tracing and error handling
        BladeSmith adds tracing and error handling code throughout the generated source code if the tracing option is set to True when you generate source code in BladeSmith.
        Utility functions generated by BladeSmith
        BladeSmith generates utility functions that it calls from other generated code.
        Edit opaque type support routines in opaque.c
        The following subsections describe the code BladeSmith generates for each routine and modifications you might need to make to the generated code.
        Edit statistics routines in statistics.c
        Edit routines in udr.c
        Compile DataBlade® module code
        This section describes how to compile DataBlade® module code.
      - Create ActiveX value objects
        This section describes how to use the to create ActiveX value objects. This section describes the use of C++ to implement opaque type support routines.
      - The ActiveX value objects
        This section provides information for client application developers who are using ActiveX value objects.
      - Programming DataBlade® modules in Java™
        This section contains information to help you edit and compile Java™ language source code generated by BladeSmith.
      - Debugging and testing DataBlade® modules on UNIX™
        This section describes how to debug and perform functional tests for DataBlade® modules written in C for Informix® on UNIX™.
      - Debugging and testing DataBlade® modules on Windows™
        This section describes how to debug and perform functional tests for DataBlade® modules written in C and C++ for Informix® on Windows™.
      - BladePack
        BladePack creates installation packages for DataBlade® modules and other software products.
      - Appendixes
        This section contains additional reference information.
    - DBDK InfoShelf
      The DataBlade® Developers Kit InfoShelf is designed to help you work with BladeSmith.
  - 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.

Server connection handle

BladeSmith calls mi_open() at the beginning of many of the routines it generates. The mi_open() call obtains a database server connection handle, which is a required argument in many DataBlade® API calls.

If your routine does not need a connection handle, remove the mi_open() and mi_close() functions that BladeSmith adds to your code.

Tip: If the only DataBlade® API call your routine makes is to mi_db_error_raise(), you do not need a connection handle. You can pass a null value to mi_db_error_raise().

For routines running in the database server address space, except the large object DataBlade® API routines, the connection handle enables client and database server routines to use the same DataBlade® API routines.

When mi_open() is called at the beginning of a generated routine, mi_close() is called to release the handle immediately before the routine returns.