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 extensionsYou 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 GuideThe Informix® DataBlade® API Programmer's Guide describes information about the DataBlade® API, the C-language application programming interface (API) provided with HCL Informix®.
Create user-defined routines
Create special-purpose UDRsThis section describes how to create special UDRs, such as iterator functions, user-defined aggregates, and optimization functions.
Provide UDR-optimization functions
Write selectivity and cost functionsThe query optimizer uses the selectivity and cost of a query to help select the best query plan. To help the optimizer select the best query plan, you can provide the query optimizer with information about the selectivity and cost of your UDR.
Obtain information about constant arguments

Obtain information about constant arguments

When the companion UDR receives an argument that is a constant, you can obtain the following information about this constant from within the cost or selectivity function.


MI_FUNCARG information	DataBlade® API function
The constant value of the companion-UDR argument	mi_funcarg_get_constant()
Determines if the value of the companion-UDR argument is the SQL NULL value	mi_funcarg_isnull()

Rate this topic

5 stars 4 stars 3 stars 2 stars 1 star

Comment on this topic.

By clicking this box, you acknowledge that you are NOT a U.S. Federal Government employee or agency, nor are you submitting information with respect to or on behalf of one. HCL provides software and services to U.S. Federal Government customers through its partners immixGroup, Inc. Contact this team at https://hcltechsw.com/resources/us-government-contact. Do not include any personal data in this Comment box.