Move backward through the table from the end, looking for a row that matches or is less than a value or full set of values in the current index.
Boolean lookupBackward( )
true if successful, false otherwise.
To specify the value for which to search, set the column value for each column in the index. The cursor is left on the first row that matches or is less than the index value. On failure (no rows less than the value being looked for) the cursor position is before the first row (isBOF).
Each search must be preceded by a call to the lookupBegin method.