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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_unlock_memory() functionThe mi_unlock_memory() function unlocks a named-memory block specified by name and memory duration.

The mi_unlock_memory() function

The mi_unlock_memory() function unlocks a named-memory block specified by name and memory duration.

Syntax

mi_integer mi_unlock_memory(mem_name, duration)
   mi_string *mem_name;
   MI_MEMORY_DURATION duration;

mem_name

The null-terminated name of the named-memory block to unlock.

duration

A value that specifies the memory duration of the named-memory block to unlock. Valid values for duration are:

PER_ROUTINE: For the duration of one iteration of the UDR
PER_COMMAND: For the duration of the execution of the current subquery
PER_STATEMENT (Deprecated): For the duration of the current SQL statement
PER_STMT_EXEC: For the duration of the execution of the current SQL statement
PER_STMT_PREP: For the duration of the current prepared SQL statement
PER_TRANSACTION: For the duration of one transaction
PER_SESSION: For the duration of the current client session
PER_SYSTEM: For the duration of the database server execution


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

Important: This advanced function can adversely affect your UDR if you use the function incorrectly. Use it only when no regular DataBlade® API function can perform the task you need done.

Usage

The mi_unlock_memory() function releases a lock on the named-memory block based on its memory duration of duration and its name, which mem_name references. The database server does not release any locks you acquire on named memory. You must ensure that your code uses the mi_unlock_memory() function to release locks in the following cases:

Immediately after you are done accessing the named memory
Before you raise an exception with the mi_db_error_raise() function
Before you call another DataBlade API function that raises an exception internally (For more information, see the HCL OneDB™ DataBlade API Programmer's Guide.)
Before the session ends
Before the memory duration of the named memory expires
Before you attempt to free the named memory with the mi_named_free() function

Important: After you obtain a lock on a named-memory block, you must explicitly release it with the mi_unlock_memory() function. Failure to release a lock before one of the previous conditions occurs can severely impact the operation of the database server.

Return values

MI_OK: The function successfully unlocked the specified named-memory block.
MI_NO_SUCH_NAME: The requested named-memory block does not exist for the specified duration.
MI_ERROR: The function was not successful.