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
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.
Choose a DataBlade® API function

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.
        Choose a DataBlade® API function
        Type of statement
        Prepared statements and input parameters
        Queries and implicit cursors
        When a DataBlade® API statement-execution function executes a query, the function must create a place to hold the resulting rows. Each of these functions (mi_exec(), mi_exec_prepared_statement(), or mi_open_prepared_statement()) automatically creates a row cursor (often called a cursor). The row cursor is an area of memory that serves as a holding place for rows that the database server has retrieved.
        Execute basic SQL statements
        The mi_exec() function provides the simplest way to send a basic SQL statement to the database server for execution. A basic SQL statement is one that does not need to be prepared. That is, the statement does not execute many times in the DataBlade® API module or it does not contain input parameters.
        Execute prepared SQL statements
        A prepared statement is an SQL statement that is parsed and ready for execution. For these statements, you prepare the statement once and execute it as many times as needed.
        Execute multiple SQL statements
        A DataBlade® API statement-execution function can send more than one SQL statement to the database server at a time. In this case, the statement string contains several SQL statements, each terminated by a semicolon (;). When the statement string contains more than one SQL statement, the mi_get_result() function executes for each statement in the string.
        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.
      - 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.

Choose a DataBlade® API function

The following table shows the functions that the DataBlade® API provides to send SQL statements to the database server for execution.

Table 1. Statement-execution functions of the DataBlade® API
Function	Type of statement	Statement executed many times or contains input parameters?	Query can use implicit cursor?
mi_exec()	Query Other valid SQL statements	No	Yes
mi_exec_prepared_statement()	Query Other valid SQL statements	Yes	Yes
mi_open_prepared_statement()	Query only	Yes	No

As the preceding table shows, you need to consider the following factors when deciding which DataBlade® API statement-execution function to use:

What type of SQL statement do you need to send?
Does your SQL statement contain input parameters?
If the SQL statement is a query, can you use an implicit cursor to access the retrieved rows?

Choose the DataBlade® API statement-execution function that is appropriate for the needs of your DataBlade® API application.