Pass a NULL connection (Server)

Use of a NULL-valued connection descriptor has the following performance impact:

• The smart-large-object functions do not need to check the validity of a connection descriptor.
• The calling code is not required to open and close a connection.

To improve performance, you can pass a NULL-valued pointer as a connection descriptor to any of the following functions of the smart-large-object interface:

• mi_lo_alter()
• mi_lo_close()
• mi_lo_colinfo_by_ids()
• mi_lo_colinfo_by_name()
• mi_lo_copy()
• mi_lo_create()
• mi_lo_decrefcount()
• mi_lo_delete_immediate()
• mi_lo_expand()
• mi_lo_filename()
• mi_lo_from_buffer()
• mi_lo_from_file()
• mi_lo_from_file_by_lofd()
• mi_lo_increfcount()
• mi_lo_invalidate()
• mi_lo_lock()
• mi_lo_lolist_create()
• mi_lo_open()
• mi_lo_spec_init()
• mi_lo_stat()
• mi_lo_stat_free()
• mi_lo_tell()
• mi_lo_to_buffer()
• mi_lo_to_file()
• mi_lo_truncate()
• mi_lo_unlock()
• mi_lo_utimes()
• mi_lo_validate()
• mi_lo_write()
• mi_lo_writewithseek()
• mi_lo_ptr_cmp()
• mi_lo_read()
• mi_lo_readwithseek()
• mi_lo_release()
• mi_lo_seek()
• mi_lo_spec_free()

The following code fragment passes a valid connection descriptor to the mi_lo_alter() function:

conn = mi_open(NULL, NULL, NULL);
if ( mi_lo_alter(conn, LO_ptr, LO_spec) == MI_ERROR )

/* Code execution does not reach here when a database server
 * exception occurs.
 */
   return MI_ERROR;
mi_close(conn);

When you specify a NULL-valued pointer as a connection descriptor, you can omit the calls to mi_open() and mi_close(), as the following code fragment shows:

if ( mi_lo_alter(NULL, LO_ptr, LO_spec) == MI_ERROR )

/* Code execution does not reach here when a database server
 * exception occurs.
 */
   return MI_ERROR;