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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_transition_type() functionThe mi_transition_type() accessor function obtains the type of state transition from a transition descriptor.

The mi_transition_type() function

The mi_transition_type() accessor function obtains the type of state transition from a transition descriptor.

Syntax

MI_TRANSITION_TYPE mi_transition_type(trans_desc)
   MI_TRANSITION_DESC *trans_desc;

trans_desc: A pointer to the transition descriptor that was passed to the callback.


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

Usage

The mi_transition_type() function obtains the transition type from the transition descriptor that trans_desc references. The DataBlade® API provides the following transition-type constants.

MI_BEGIN: The database server begins a new transaction.
MI_NORMAL_END: The database server ended the current transaction by committing the transaction.
MI_ABORT_END: The database server ended the current transaction by rolling back (aborting) the transaction.

This function is useful within a state-transition or all-events callback to determine the current transition type.

Server only: In a C UDR routine, the following state-transition events occur at a change in transition type:

MI_EVENT_SAVEPOINT
MI_EVENT_COMMIT_ABORT
MI_EVENT_POST_XACT
MI_EVENT_END_STMT
MI_EVENT_END_XACT
MI_EVENT_END_SESSION

These events occur only for the MI_NORMAL_END and MI_ABORT_END state transitions.

Client only: In a client LIBMI application, the state-transition event MI_Xact_State_Change occurs at a change in transition type. This event occurs for all state transitions: MI_BEGIN, MI_NORMAL_END, and MI_ABORT_END.

For a description of the transition descriptor, see the HCL OneDB™ DataBlade API Programmer's Guide.

Return values

MI_BEGIN: The database server just began a new transaction.
MI_NORMAL_END: The database server just committed the transaction.
MI_ABORT_END: The database server just rolled back (aborted) the transaction.
MI_ERROR: The function was not successful.