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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_seek() functionThe mi_lo_seek() function sets the LO seek position for the next read or write operation on an open smart large object.

The mi_lo_seek() function

The mi_lo_seek() function sets the LO seek position for the next read or write operation on an open smart large object.

Syntax

mi_integer mi_lo_seek(conn, LO_fd, offset, whence, seek_pos)
   MI_CONNECTION *conn;
   MI_LO_FD LO_fd;
   mi_int8 *offset;
   mi_integer whence;
   mi_int8 *seek_pos;

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_fd

An LO file descriptor for the smart large object whose seek position you want to change. A previous call to mi_lo_open() obtains this descriptor.

offset

A pointer to the eight-byte integer (mi_int8) offset from the specified whence seek position.

whence

This value determines how the offset value is interpreted.

seek_pos

A pointer to the eight-byte integer (mi_int8) that identifies the new LO seek position.


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

Usage

The mi_lo_seek() function uses the whence and offset arguments to determine the new LO seek position of the smart large object that LO_hdl identifies, as follows:

The whence argument identifies the position from which to start the seek operation.
Valid values include the following whence constants.

Whence constant
Starting seek position

MI_LO_SEEK_SET

The start of the smart large object

MI_LO_SEEK_CUR

The current LO seek position in the smart large object

MI_LO_SEEK_END

The end of the smart large object
The offset argument identifies the offset, in bytes, from the starting seek position (which the whence argument specifies) at which to begin the seek.
This offset value can be negative for all values of whence. For more information about how to access eight-bit (INT8) integers, see the HCL OneDB™ DataBlade® API Programmer's Guide.

The mi_lo_seek() function returns the new seek position in the mi_int8 seek_pos variable.

Server only: The mi_lo_seek() 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.

To obtain the current seek position, use the mi_lo_tell() function.

Return values

MI_OK: The function was successful.
MI_ERROR: The function was not successful.