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Extending HCL OneDB™Beyond standard relational database objects, HCL OneDB™ can be extended to handle specialized data types, access methods, routines, and other objects. HCL OneDB™ includes many built-in extensions that are fully integrated in the database server. HCL OneDB™ 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 HCL OneDB™.
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 HCL OneDB™ databases.
DataBlade® Developers KitThe 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 OneDB™ databases.
DataBlade® Developers Kit User's GuideThe HCL OneDB™ DataBlade® Developers Kit Users Guide describes how to use OneDB® DataBlade® Developers Kit (DBDK) tools to develop and package DataBlade® modules.
Create DataBlade® objects by using BladeSmithUse BladeSmith to create DataBlade® modules.
Create DataBlade® module objectsBladeSmith uses wizards to create and edit objects.
Create data typesYou can create extended data types in BladeSmith. In addition, you must define qualified built-in data types before you can use them in a BladeSmith project.
Opaque data typeAn opaque data type is a C structure or C++/ActiveX class. The database server does not interpret the contents of the structure. Instead, it calls support routines that you provide to manipulate the structure.
Support routinesYou can select from different categories of support routines to support your opaque data type.
Statistics support (not available for C++ or Java™)Statistics support is available with HCL OneDB™ Version 9.2 and later.

Statistics support (not available for C++ or Java)

Statistics support is available with HCL OneDB™ Version 9.2 and later.

This category is valid for the C language.

User-defined statistics provide a way to improve performance when you compare opaque data type values. User-defined statistics compile information about the values in an opaque data type column that the query optimizer can use when it creates a query plan.

You can define statistics support functions for an opaque data type and then a selectivity function for a routine that takes opaque data types as its arguments.

Statistics support functions are OpaqueStatCollect(), OpaqueStatPrint(), Opaque_SetMinValue(), Opaque_SetMaxValue(), and Opaque_SetHistogram().

Tip: Statistics support functions are in the statistics.c source code file, instead of in the opaque.c source code file with all other opaque data type support routines.