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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.
User-Defined Routines and Data Types Developer's GuideThe HCL OneDB™ 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 OneDB™.
Improve UDR performance
Optimize functions in SQL statements
Specify cost and selectivity
Constant cost and selectivity values

Constant cost and selectivity values

The following modifiers specify a cost or selectivity value when you execute the CREATE FUNCTION statement. The cost or selectivity value does not change for each invocation of the function:

percall_cost=integer
The percall_cost modifier specifies the cost of executing the function once. The integer value is a number.
selconst=float
The selconst modifier specifies the selectivity of a function. The float value is a floating-point number between 0 and 1 that represents the fraction of the rows for which you expect the routine to return TRUE.