- (BOOL) readField:(NSInteger) recno;

Function readField() reads a single field to internal memory block.
After reading you can use functions getString(), getValue(), getDateTime(), getTicks(), getMemoBuf()

{
    // your code
    for( NSInteger row = 0; row < [dbf recCount]-1; row++ )
    {    
        [dbf readField:row fieldno:field];
        // your code
    }
}