Home
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_collection_card() functionThe mi_collection_card() function returns a count of the elements in a collection (that is, its cardinality).

The mi_collection_card() function

The mi_collection_card() function returns a count of the elements in a collection (that is, its cardinality).

Syntax

mi_integer mi_collection_card(coll_ptr, isnull)
   MI_COLLECTION *coll_ptr;
   mi_boolean *isnull;

coll_ptr

A valid pointer to a collection structure.

isnull

A valid pointer to an SQL NULL indicator flag, which can have either of the following values:

MI_TRUE: The collection value is SQL NULL.
MI_FALSE: The collection value is not SQL NULL. The collection contains zero or more elements.


Valid in client LIBMI application?	Valid in user-defined routine?
Yes	Yes

Usage

The mi_collection_card() function returns the cardinality of the collection that coll_ptr references. The collection value can be SQL NULL, in which case the isnull flag is set to MI_TRUE and the return value is 0. A collection does not have to be open for mi_collection_card() to obtain its cardinality.

Return values

0: (isnull = MI_TRUE) indicates the collection value is SQL NULL.
>=0: (isnull = MI_FALSE) provides the cardinality of the collection.
MI_ERROR: An invalid parameter.