Using Derived column we can prepare the input. We will provide yyyy-MM-dd to the final conversion:
Year: (DT_STR,4,1252)(DataDate / 10000)
Month: (DT_STR,2,1252)(DataDate / 100 % 100)
Day: (DT_STR,2,1252)(DataDate % 100)
All together: (DT_DBDATE)((DT_STR,4,1252)(DataDate / 10000) + "-&q...