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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® API Function ReferenceThe HCL OneDB™ DataBlade® API Function Reference describes the DataBlade® API functions and the subset of functions that the DataBlade® API supports.
Function descriptionsThis section gives comprehensive reference information about the functions that are valid within DataBlade® API modules. It lists the function descriptions in alphabetical order, with syntax, usage information, and return values for the functions.
The mi_funcarg_isnull() functionThe mi_funcarg_isnull() function determines whether the companion-UDR argument of a cost or selectivity function contains the SQL NULL value.

The mi_funcarg_isnull() function

The mi_funcarg_isnull() function determines whether the companion-UDR argument of a cost or selectivity function contains the SQL NULL value.

Syntax

mi_boolean mi_funcarg_isnull(funcarg_ptr)
   MI_FUNCARG *funcarg_ptr;

funcarg_ptr: A pointer to the MI_FUNCARG structure that describes the companion-UDR argument.


Valid in client LIBMI application?	Valid in user-defined routine?
No	Yes

Usage

The mi_funcarg_isnull() function determines whether the argument from the MI_FUNCARG structure that funcarg_ptr references contains the SQL NULL value. The MI_FUNCARG structure describes an argument of an expensive UDR to its cost or selectivity function. Use the mi_funcarg_isnull() function only for companion-UDR arguments that are constant values; that is, only arguments for which the mi_funcarg_get_argtype() function returns the MI_FUNCARG_CONSTANT value.

Use the mi_funcarg_isnull() function in a cost or selectivity function to determine if the value of an argument passed into the companion UDR is the SQL NULL value.

Return values

MI_TRUE: The companion-UDR argument contains the SQL NULL value.
MI_FALSE: The companion-UDR argument does not contain the SQL NULL value.
MI_ERROR: The function was not successful.