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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_lo_validate() functionThe mi_lo_validate() function checks whether a given LO handle is valid.

The mi_lo_validate() function

The mi_lo_validate() function checks whether a given LO handle is valid.

Syntax

mi_integer mi_lo_validate(conn, LO_hdl)
   MI_CONNECTION *conn;
   MI_LO_HANDLE *LO_hdl;

conn

This value is one of the following connection values:

A pointer to a connection descriptor established by a previous call to mi_open(), mi_server_connect(), or mi_server_reconnect().

A NULL-valued pointer (database server only)

LO_hdl

A pointer to the LO handle to validate.


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

Usage

The mi_lo_validate() checks whether the LO handle that LO_hdl references is valid. An LO handle might be invalid for any of the following reasons:

The memory address is invalid or NULL.
The LO handle contains invalid reference data because:
- It was never set to a valid value.
- It was explicitly invalidated with the mi_lo_invalidate() function.

You can use the mi_lo_validate() function in the support function of an opaque data type that contains smart large objects. In the lohandles() support function, this function can determine unambiguously which LO handles are valid for the given instance of the opaque type.

If mi_lo_validate() fails because of an invalid connection, callbacks are invoked.

Server only: The mi_lo_validate() function does not need a connection descriptor to execute. If your UDR does not need a valid connection for other operations, you can specify a NULL-valued pointer for the conn parameter to establish a NULL connection. For information about the advantages of a NULL connection, see the HCL OneDB™ DataBlade® API Programmer's Guide.

Return values

0: The LO handle that LO_hdl references is valid.
>0: The LO handle that LO_hdl references is invalid.
MI_ERROR: The connection was invalid.