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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.
Process statement results
Execute the mi_get_result() loop

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
        Execute the mi_get_result() loop
        Handling unsuccessful statements
        Handling a DDL statement
        The mi_get_result() function returns a status of MI_DDL to indicate that the current statement was a DDL statement that has successfully executed. When you receive the MI_DDL statement status, you can use the mi_result_command_name() function to obtain the name of the DDL statement that executed as the current statement.
        Handling a DML Statement
        The mi_get_result() function returns a status of MI_DML to indicate that the current statement is a data manipulation (DML) statement that has successfully executed.
        Handling query rows
        Handling no more results status
        The mi_get_result() function returns a status of MI_NO_MORE_RESULTS to indicate that statement processing for the current statement is complete.
        Example: The get_results() function
        The user function, get_results(), demonstrates the mi_get_result() row-retrieval loop, controlled with the mi_get_result() function. It also demonstrates the use of the mi_result_command_name() function to get the name of the current statement and the mi_result_row_count() function to get the number of rows affected by this statement.
        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.
      - 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.

Execute the mi_get_result() loop

The mi_get_result() function is usually executed in a loop after one of the DataBlade® API statement-execution functions sends a statement to the database server. The function is normally called in the outermost loop of row-retrieval code. This loop executes for each of several states of the database server as it processes statement results. These states are represented as the status of the current statement.

For a list of statement-execution functions see Statement-execution functions of the DataBlade API.

The mi_get_result() function can return the following status information.


Information about current SQL statement	Statement-status constant
The current statement has generated an error.	MI_ERROR
The current statement is a data definition (DDL) statement that has completed successfully.	MI_DDL
The current statement is a data manipulation (DML) statement that has completed successfully.	MI_DML
The current statement is a query that has executed successfully.	MI_ROWS
No more results are pending for the current statement.	MI_NO_MORE_RESULTS

You can use a switch statement based on these statement-status constants to determine how to handle the status of the current statement. The mi_get_result() loop terminates when mi_get_result() returns the status MI_NO_MORE_RESULTS. Think of the mi_get_result() loop as an iteration over the states of the database server.