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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® 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
Execute SQL statements
One basic task of a DataBlade® API module is to send SQL statements to the database server for execution.
Save sets
Save sets provide a mechanism for a DataBlade® API module to access several rows simultaneously.
Free a save set

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 SQL statements
        To execute an SQL statement, a DataBlade® API module must send the SQL statement to the database server, where the statement is executed.
        Process statement results
        Retrieving query data
        Complete execution
        The DataBlade® API provides functions to complete execution of the current statement.
        Inserting data into the database
        To insert a row of data into a database, you must execute the INSERT statement.
        Save sets
        Save sets provide a mechanism for a DataBlade® API module to access several rows simultaneously.
        Create a save set
        You create a save set with mi_save_set_create(), which returns a pointer to a save-set structure (MI_SAVE_SET).
        Inserting rows into a save set
        The mi_save_set_insert() function inserts a row into a save set.
        Building a save set
        To build a save set, a DataBlade® API module can create a save set and fetch rows into it from the mi_next_row() loop.
        Free a save set
      - 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
    - 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.

Free a save set

A save-set structure has a memory duration of PER_STMT_EXEC. Therefore, a save-set structure remains active until one of the following events occurs:

The mi_save_set_destroy() function frees the save-set structure.
The end of the current SQL statement is reached.
The mi_close() function closes the current connection.

To conserve resources, use the mi_save_set_destroy() function to explicitly deallocate the save set once your DataBlade® API module no longer needs it. The mi_save_set_destroy() function is the destructor function for a save-set structure. It frees the save-set structure and any resources that are associated with it.