I do not think that SSIS documentation highlights enough the following problem. I had a Data Transfer task based on a table. It was running fine, but then we decided to change the size of the field on both source and target table.
During the next run the packages reported "Validation warning. table_name: connection_name: Truncation may occur due to inserting data from data flow column "column_name" with a length of 50 to database column "column_name" with a length of 10."
To resolve this, I had to:
- open the Data Flow task
- open Advanced Editor (on OLE DB source)
- go to Input and Output Properties tab
- expand OLE DB Source Output
- expand Output Columns
- click on column
- change Length property of the column
I also went to target side:
- open Advanced Editor (on OLE DB Destination)
- go to Input and Output Properties tab
- Click on Refresh button
I do not know when exactly is needed, but I've noticed that results of Edit and Advanced Edit are not always leaving the package in synch, so…
- open Editor (on both OLE DB Source and Destination) and simply close it