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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_func_desc_by_typeid() functionThe mi_func_desc_by_typeid() function looks up a registered user-defined routine by its routine identifier and creates its function descriptor.

The mi_func_desc_by_typeid() function

The mi_func_desc_by_typeid() function looks up a registered user-defined routine by its routine identifier and creates its function descriptor.

Syntax

MI_FUNC_DESC *mi_func_desc_by_typeid(conn, routine_id)
   MI_CONNECTION *conn;
   mi_funcid *routine_id;;

conn: A pointer to a connection descriptor established by a previous call to mi_open(), mi_server_connect(), or mi_server_reconnect().
This value can be a pointer to a session-duration connection descriptor established by a previous call to mi_get_session_connection(). Use of a session-duration connection descriptor is an advanced feature of the DataBlade® API.
routine_id: The routine identifier that uniquely identifies the UDR within the sysprocedures system catalog table.


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

Usage

The mi_func_desc_by_typeid() function creates a function descriptor for the UDR that the routine_id argument specifies. The routine_id argument provides the routine identifier of the UDR. The function is one of the functions of the Fastpath interface. It is a constructor function for the function descriptor.

Tip: The DataBlade API provides the mi_funcid data type to hold routine identifiers. The mi_funcid data type has the same structure as the mi_integer data type. For compatibility with earlier versions, some DataBlade API functions still assume that routine identifiers are of type mi_integer.

This function performs the following tasks:

Looks for a user-defined routine that matches the routine_id routine identifier in the sysprocedures system catalog table
Allocates a function descriptor for the UDR and saves the routine sequence in this descriptor
Allocates an MI_FPARAM structure for the routine and saves the argument and return-value information in this structure
Returns a pointer to the function descriptor that it has allocated for the user-defined routine

Server only: When you pass a public connection descriptor (from mi_open()), the mi_func_desc_by_typeid() function allocates the new function descriptor in the PER_COMMAND memory duration. If you pass a session-duration connection descriptor (from mi_get_session_connection()), mi_func_desc_by_typeid() allocates the new function descriptor in the PER_SESSION memory duration. This function descriptor is called a session-duration function descriptor. For more information, see the HCL OneDB™ DataBlade API Programmer's Guide.

The session-duration connection descriptor and session-duration function descriptor are advanced features of the DataBlade API. They can adversely affect your UDR if you use them incorrectly. Use them only when a regular connection descriptor or function descriptor cannot perform the task you need done.

Return values

An MI_FUNC_DESC pointer

A pointer to the function descriptor for the UDR that routine_id identifies.

NULL

No matching user-defined routine was found or that the specified user-defined routine has multiple return values, which is possible with the following routines:

SPL routines that include the WITH RESUME clause in the RETURN statement
Iterator functions