SSIS 2008 Script Transformation Inputs and Outputs

I have a flat file that I need to parse in SSIS, part of this parsing is to chop off a load of extra text at the bottom of the file. To help do this I added a row number to each row using a Script Transformation.

In the Script Transformation (ST) under Inputs and Outputs I have an Input Column defined called Column256_in (it has a length of 256) and its ID is 59.

For Output columns I have defined Column256_out, it has an ID of 68 and a MappedColumnID of 59, there is another Output Col called rowCount.

There is script c开发者_JS百科ode contained in the ST the calculates the row number for each row.

When I run the SSIS package I have a Data Grid after the Script Transformation I get the following:

Column256_in contains the data from the orginal text file.

rowCount is populated correctly. ( I did something right today!)

Column256_out is empty --> I thought that the MappedColumnId of 59 would populate this col with the data from Column256_in.

What does the MappedColumnID attribute do on the Out put col?

Thanks for your assistance.

KD

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MappedColumnID is just an alternative way of identifying the columns instead of using their names.

From MSDN

The use of these properties is not required. These properties provide an easier way for developers to associate related columns, such as input and output columns, in custom data flow components.