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.

Custom Property for Remove Duplicates transform Input Row

Im working through the MS example of "removeDuplicates". I cant seem to figure out how to add custom property for input column.

I added the helper method:
private static void AddIsKeyCustomPropertyToInput(IDTSInput90 input, object value)
{
IDTSCustomProperty90 isKey = input.CustomPropertyCollection.New();
isKey.Name = "IsKey";
isKey.Value = value;
}
I call it from:
public override void ProvideComponentProperties()
{
//...
AddIsKeyCustomPropertyToInput(input, false);
//...
}
public override void ReinitializeMetaData()
{
IDTSInput90 input = ComponentMetaData.InputCollection[0];
if (input.CustomPropertyCollection.Count == 0)
{
AddIsKeyCustomPropertyToInput(input, false);
}
// ...
}

However when I deployed it and added the component to SSIS package - I cant see the Custom Column "IsKey" in the input column properties window.
What am I missing - please help As stated by some fore-sightful guy in a blog -

the way to SSIS enlightment is treacherous

. it seems i was missing something very basic - i was trying to set custom property for the whole input instead of just input column.

So instead of 2 above mentioned calls (in ProvideComponentProperties and ReinitializeMetaData ) i needed to set it in following:

public override IDTSInputColumn90 SetUsageType(int inputID, IDTSVirtualInput90 virtualInput, int lineageID, DTSUsageType usageType)
{
if (virtualInput == null)
{
throw new ArgumentNullException("virtualInput");
}

IDTSVirtualInputColumn90 vCol = virtualInput.VirtualInputColumnCollection.GetVirtualInputColumnByLineageID(lineageID);
IDTSInputColumn90 col = null;

/// No support for BLOB image columns.
if (vCol.DataType == DataType.DT_IMAGE)
throw new Exception("Binary data types not supported.");

/// If the usageType is UT_IGNORED, then the column is being removed.
/// So remove it from the outputs also.
if (usageType == DTSUsageType.UT_IGNORED)
{
/// ...
}
else
{
/// Let the base class add the input column.
col = base.SetUsageType(inputID, virtualInput, lineageID, usageType);
// Store the lineageID of the input column in a custom property of the output column.
IDTSCustomProperty90 inputColIsKey = col.CustomPropertyCollection.New();
inputColIsKey.Name = "IsKey";
inputColIsKey.Value = false;

/// Add an output column to the distinct and duplicate outputs.
AddOutputColumn(ComponentMetaData.OutputCollection[0].ID, col);
AddOutputColumn(ComponentMetaData.OutputCollection[1].ID, col);
}
return col;
}

Hopefully - when i have created this transform to filter duplicates based on (Primery) Key column(s) i can post it in my blog (to be created)|||Now if only I could figure out how to pass this custom "IsKey" property to class "Row" Equals operator and to class "Buffer" sort method

Custom Component - Change Data Type

I am developing a custom pipeline component (my first real one) which will handle input columns in a DT_NUMERIC format and convert them to a DT_DATE format. Sort of like the included Data Conversion component, but with some built in business logic. The Data Conversion component puts the converted data in a new column in the output buffer. I would like to keep the data in the same column. So, in my input buffer the column would be of type DT_NUMERIC, but in the output buffer I want to make it DT_DATE.

What is the best approach to do this?

-DarrellUnless you want you component to have to copy data from the input to the ouput you can not do this. There are 2 types of outputs, synchronous and asynchronous. The synchronous one is simple and requires no data copying or column creation (except of course for the new column you would produce of the DT_DATE type). However, because of this you can't change column types and that is why the derived column doesn't allow this. The asynchronous one is complex. You have to create all the output columns and keep them in sync with the input columns and know how to map the input columns to the output columns so that you can copy the data to the correct place. My advise is use a sync output and live with the additional column unless it is absolutely necessary to use and async output.

HTH,
Matt