Insert null value in Database through SSIS

The inbound file had empty string that was causing the file to error when it was trying to insert in the DOB column of the table with the data type on datetime. I used a dervied coulum in the DFT and used the following the the data tranformation editor to solve the error ISNULL(DOB) || TRIM(DOB) == "" ? NULL(DT_DBDATE) : (DT_DBDATE)DOB When the file was loaded the DOB column had NULL for the empty value.