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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.
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.
SQL statements for access methods
These topics describe the syntax and usage of the ALTER ACCESS_METHOD, CREATE SECONDARY ACCESS_METHOD, and DROP ACCESS_METHOD statements, which insert, change, or delete entries in the sysams system catalog table.

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.
  - 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.
    - Access methods
      This section describes access methods, explains why you create user-defined access methods, and shows you how to create user-defined access methods
    - Develop an access method
      These topics describe the steps that you take to implement a user-defined access method with the Virtual-Index Interface (VII).
    - Design decisions
      These topics present the choices that you make to optimize the performance and flexibility of the access method that you can create with the virtual-index interface (VII).
    - Purpose-function reference
      These topics describe the purpose functions that the access-method developer provides.
    - Descriptor function reference
    - SQL statements for access methods
      These topics describe the syntax and usage of the ALTER ACCESS_METHOD, CREATE SECONDARY ACCESS_METHOD, and DROP ACCESS_METHOD statements, which insert, change, or delete entries in the sysams system catalog table.
      - The ALTER ACCESS_METHOD (+) statement
        The ALTER ACCESS_METHOD statement changes the attributes of a user-defined access method in the sysams system catalog table.
      - The CREATE ACCESS_METHOD (+) statement
        Use the CREATE SECONDARY ACCESS_METHOD statement to register a new secondary access method. When you register an access method, the database server places an entry in the sysams system catalog table.
      - The DROP ACCESS_METHOD (+) statement
        Use the DROP ACCESS_METHOD statement to remove a previously defined access method from the database.
      - Purpose options
        The database server recognizes a registered access method as a set of attributes, including the access-method name and options called purposes.
    - XA-compliant external data sources
      The HCL Informix® Transaction Manager recognizes XA-compliant external data sources, which can participate in two-phase commit transactions.

SQL statements for access methods

These topics describe the syntax and usage of the ALTER ACCESS_METHOD, CREATE SECONDARY ACCESS_METHOD, and DROP ACCESS_METHOD statements, which insert, change, or delete entries in the sysams system catalog table.

This section also provides the valid purpose-function, purpose-flag, and purpose-value settings.