Welcome
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 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.
Programmer's Guide
The HCL® Informix® DataBlade® API Programmer's Guide describes information about the , the C-language application programming interface (API) provided with HCL Informix.
Data manipulation
Date and time data types
This section describes the date and time data types and the functions that the supports to process date and time data.
Date data
Date data is a calendar date. The provides support for date values in both their text and binary representations.
Conversion of date representations
Both the library and the library provide functions that convert from the text (string) representation of a date value to the binary (internal) representation for DATE.
functions for date conversion
The provides functions for conversion between text and binary representations of date data.

HCL Informix® V15.0.0 documentation
Welcome to the documentation for HCL Informix® 15.0.0 and related client tools and products.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
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 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 modules
  These topics describe how to use built-in database extensions and separately installed 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.
  - Programmer's Guide
    The HCL® Informix® DataBlade® API Programmer's Guide describes information about the , the C-language application programming interface (API) provided with HCL Informix.
    - overview
    - Data manipulation
      - Numeric data types
        This section describes these numeric data types and the functions that the supports to process numeric data.
      - Date and time data types
        This section describes the date and time data types and the functions that the supports to process date and time data.
        Date data
        Date data is a calendar date. The provides support for date values in both their text and binary representations.
        Date text representation
        Date binary representation
        The SQL DATE data type holds the internal (binary) format of a decimal value. This value is an integer value that represents the number of days since December 31, 1899. Dates before December 31, 1899, are negative numbers, while dates after December 31, 1899, are positive numbers.
        Transfers of date data (Server)
        For date data to be portable when transferred across different computer architectures, the provides functions to handle type alignment and byte order.
        Conversion of date representations
        Both the library and the library provide functions that convert from the text (string) representation of a date value to the binary (internal) representation for DATE.
        functions for date conversion
        The provides functions for conversion between text and binary representations of date data.
        ESQL/C functions for date conversion
        The function library provides functions to convert a DATE (mi_date) value to and from char strings.
        Operations on date data
        The library provides functions to perform operations on DATE (mi_date) values.
        Date-time or interval data
        The provides support for date-time or interval data in both text and binary representations.
      - Complex data types
        This section describes the complex data types and the functions that the supports to process collection and row-type data.
      - Smart large objects
    - Database access
    - Create user-defined routines
    - Appendix
      This section contains additional reference information.
  - Function Reference
    The IBM® Informix® DataBlade® API Function Reference describes the functions and the subset of functions that the supports.
  - Developers Kit
    The Developers Kit (DBDK) guides contain information about the tools you can use to develop and package modules, which extend the functionality of HCL Informix® databases.
  - J/Foundation Developer's Guide
    The HCL® 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 HCL® 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 HCL® 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 IBM® 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 IBM® 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 module.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.

functions for date conversion

The provides functions for conversion between text and binary representations of date data.

Table 1. functions for date conversion
function	Convert from	Convert to
mi_date_to_string()	DATE (mi_date)	Date string
mi_string_to_date()	Date string	DATE (mi_date)

Server only: The mi_date_to_string() and mi_string_to_date() functions are useful in the input and output support functions of an opaque data type that contains mi_date values. They allow you to convert DATE values between their external format (text) and their internal (binary) format when transferred to and from client applications.

The mi_date_to_string() and mi_string_to_date() functions use the current processing locale to handle locale-specific formats in the date string. For more information, see the HCL® Informix® GLS User's Guide.