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.
Database access
XA-compliant external data sources
Overview of integrating XA-compliant data sources in transactions
The transaction manager, which is an integral part of the database server, not a separate module, can invoke support routines for each XA-compliant, external data source that participates in a distributed transaction at a particular transactional event, such as prepare, commit, or rollback. This interaction conforms to X/Open XA interface standards.

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
    - Database access
      - Connection handling
        This section describes how to initialize, establish, and close connections.
      - Execute SQL statements
        One basic task of a DataBlade® API module is to send SQL statements to the database server for execution.
      - Execute user-defined routines
        This section provides information about how to call a user-defined routine (UDR).
      - Exceptions and events
        This section describes exceptions and events, and explains how to handle them in DataBlade® API modules.
      - XA-compliant external data sources
        Overview of integrating XA-compliant data sources in transactions
        The transaction manager, which is an integral part of the database server, not a separate module, can invoke support routines for each XA-compliant, external data source that participates in a distributed transaction at a particular transactional event, such as prepare, commit, or rollback. This interaction conforms to X/Open XA interface standards.
        Support for the two-phase commit protocol
        HCL Informix® supports the two-phase commit protocol with registered XA-compliant data sources. The two-phase commit protocol ensures that transactions are uniformly committed or rolled back across multiple database servers. This protocol governs the order in which commit transactions are performed and provides a recovery mechanism in case a transaction does not execute.
        XA-compliant data sources and data source types
        An XA-compliant data source type is a type of data source that is capable of supporting XA protocol requirements for a resource manager that is participating in a transaction.
        Infrastructure for creating support routines for XA routines
        Global transaction IDs
        The transaction manager automatically generates and maintains a global transaction ID (of type XID) for each distributed XA transaction in the system. The transaction manager can use the same XID for transactions on different databases.
        System catalog tables
        The sysxasourcetypes system catalog table stores information about XA data-source types. The sysxadatasources system catalog table stores information about XA data-source instances.
        Files containing necessary components
        DataBlade® modules obtain the XA-defined return values, the XID structure definition, and other necessary information from the from the $INFORMIXDIR/incl/public/xa.h file.
        Create user-defined XA-support routines
        You can create user-defined XA-support routines, such as xa_open(), xa_start(), xa_prepare(), xa_rollback(), xa_commit(), xa_recover(), xa_complete(), xa_forget(), xa_close(), and xa_end(). These purpose functions are used for transaction management.
        Create and drop XA data sources and data source types
        This section contains information about creating and dropping XA-compliant data source types and instances of XA-compliant data sources.
        Register and unregister XA-compliant data sources
        After you create an external XA-compliant data source, transactions can register data source using the mi_xa_register_xadatasource() or ax_reg() functions. You can also unregister the data source using the mi_xa_unregister_xadatasource() or ax_unreg() functions.
        Monitor integrated transactions
    - 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.

Overview of integrating XA-compliant data sources in transactions

The transaction manager, which is an integral part of the database server, not a separate module, can invoke support routines for each XA-compliant, external data source that participates in a distributed transaction at a particular transactional event, such as prepare, commit, or rollback. This interaction conforms to X/Open XA interface standards.

Transaction support in HCL Informix® for XA-compliant, external data sources, which are also called resource managers, enables you to:

Create XA-compliant, external data source types and instances of XA-compliant, external data sources.
Create XA purpose functions, such as xa_prepare, xa_commit, and xa_rollback, for each XA data source type to keep external data in sync with HCL Informix® transactional semantics.
Register XA-compliant, external data sources with anHCL Informix® transaction.
Unregister XA-compliant, external data sources.
Use multiple XA-compliant, external data sources within the same global transaction.

The transaction coordination with an XA-compliant, external data source is supported only in HCL Informix® logged databases and ANSI-compliant databases. These databases support transactions. Transaction coordination with an XA-compliant, external data source is not supported in non-logged databases.

This section contains information about the following processes:

Creating user-defined XA-support routines
Creating and dropping XA-compliant, external data source types.
Creating and dropping XA-compliant, external data sources.
Registering and unregistering XA-compliant, external data sources as needed.

The HCL Informix® MQ DataBlade® Module, which provides a set of user-defined routines (UDRs) to enable HCL Informix® applications to exchange messages between HCL Informix® and HCL Informix® MQ, uses the XA data-source functionality described in this section. For information about the MQ DataBlade® Module, see the Informix® Database Extensions User's Guide.

For general information about XA specifications, refer to the "Distributed Transaction Processing: The XA Specification." This is the X/Open standard specification that is available on the internet.

At the present time, the transaction manager does not support the asynchronous execution of purpose functions, thread migration, and transaction branch features.