Custom transform component, change type or add output column

Would anyone happen to have any pointers or know of any good code examples to either programmatically change the type of an input column when it is passed through the component, or add a new column to the output? I am extracting data from an Oracle database which is in Julian date format (represented within SSIS as a DT_NUMERIC column) and I need to to either transform the input column holding it into a date column, or to dynamically add a new output column holding the transformed data.

Many thanks

You cannot change the type of a buffer column. You will have to add a new column. If you only expect users to select valid columns, and for each one selected you could handle this by overriding SetUSageType on the component class.

Whenever people select a column (UsageType read-only, deny read-write as not required), you could then add a new output column. This would work and would be quite clean.

I would also use a custom property on the output column to store the lineage ID of the "source" inpurt column.

The better way would be to handle adding the column outside of SetUsageType. So with the Advanced UI you would need to select the input column (SetUsageType), then add the output column (InsertOutputColumnAt) and add the custom property (SetOutputColumnProperty) all in three steps. Method names used by the UI are shown in braclets so you know what to do if it was your own UI. With a proper custom UI this of course would become one step for the end user, but more importantly could all be done through the managed wrapper interface, CManagedComponentWrapperClass.SetUsageType, InsertOutputColumnAt, SetOutputColumnProperty methods. This would be good for the user experience it will give around real-time validation and OK/Cancel behaviour of the UI.