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Cursor Association Functions (keyscan)
Collaboration diagram for Cursor Association Functions (keyscan):

Functions

RDM_RETCODE rdm_cursorGetRowsByKeyAtPosition (RDM_CURSOR sourceCursor, RDM_KEY_ID keyId, RDM_CURSOR *pCursor)
 Associate an RDM_CURSOR with a row set based on a key and positioned to the same row as the source cursor. More...
 

Detailed Description

Core cursor association API for retrieving rows in key order positioned at a given row. All the fuctions here are located in RDM DB Engine Library. Linker option:

    -lrdmrdm

See cursor for a more detailed description of a cursor.

Function Documentation

◆ rdm_cursorGetRowsByKeyAtPosition()

RDM_RETCODE rdm_cursorGetRowsByKeyAtPosition ( RDM_CURSOR  sourceCursor,
RDM_KEY_ID  keyId,
RDM_CURSOR pCursor 
)

#include <rdmcursorapi.h>

Associate an RDM_CURSOR with a row set based on a key and positioned to the same row as the source cursor.

This function associates the RDM_CURSOR pointed to by pCursor with a row set ordered by the specified key. The row set contains all of the rows for the table that the specified key column is in. The cursor will be positioned to the current row of sourceCursor.

If sourceCursor is not at a row that is a valid row of the specified key an error will be returned and cursor will not be associated.

sourceCursor can be any type of RDM_CURSOR as long as the current row of sourceCursor is a valid row for the specified key.

Cursor Association Rules
  • If pCursor points to NULL then a new cursor will be allocated and associated with the same RDM_DB as sourceCursor.
  • If pCursor points to an RDM_CURSOR that has been allocated, but not associated with an RDM_DB then the RDM_CURSOR will be associated with the same RDM_DB as sourceCursor.
  • If pCursor points to an RDM_CURSOR that is associated with an RDM_DB other than the RDM_DB associated with sourceCursor then an error will be returned.
  • If pCursor points to a RDM_CURSOR that has been previously used and held a set of rows from a different table then memory may need to be reallocated to handle the new set of rows. If you are interacting with more than one set of tables it can be more efficient to use multiple RDM_CURSOR than to share a single RDM_CURSOR.
Locking Requirements
Read lock on the table associated with the sourceCursor
Return values
sOKAYNormal, successful return.
eNOSTARTREADA read operation was attempted when no rdm_dbStartSnapshot(), rdm_dbStartRead(), or rdm_dbStartUpdate() is active.
eNOTLOCKEDAttempt to access a table for reading or update without proper locks.
eDBNOTOPENDatabase not open.
eNOCURRENTROWThe cursor is not positioned to a valid row.
eOWNERDELETEDThe owner row for a set cursor has been deleted.
eSINGLETONDELETEDThe row for a singleton cursor has been deleted.
See also
rdm_dbStartRead
rdm_dbStartSnapshot
rdm_dbStartUpdate
rdm_dbGetRows
rdm_cursorGetMemberRows
rdm_cursorGetOwnerRow
rdm_cursorGetRowsAtPosition
rdm_cursorGetRowsInReverseOrder
rdm_cursorGetSelf
rdm_cursorGetSiblingRows
rdm_cursorGetClone
rdm_cursorMoveToNext
rdm_cursorReadRow
rdm_cursorUpdateRow
rdm_cursorDeleteRow
rdm_cursorLinkRow
Parameters
[in]sourceCursorThe cursor whose current row will be used for the resulting cursor position
[in]keyIdThe RDM key id
[out]pCursorA pointer to an RDM_CURSOR (must be allocated, associated with db, or set to NULL)