Expression -puzzling(help needed)

Question

Hi All,
Is there a possibility that my expression fails on the first run trying to load into a column in the table having truncation error,but ultimately runs at the second time(having that column alone empty while populating other columns?).
Help needed...ANy help on this topic wil be much helpful!!

Answer 1

Hi ssislara,
If I understand correctly, a derived column with expression fails in the first time when execution the package, but it works fine after change the source column to another column that has more length with empty. For example, use the expression (DT_WSTR,4)[column_name]
as the derived column, the original column is nchar(10) with value like ‘abcd’, the later column is nvarchar(50) with value like ‘abcd’.
If in this scenario, the issue you said is possible. Because nchar(10) is Fixed-length Unicode string data, nvarchar(50) is Variable-length Unicode string data. The expression (DT_WSTR,4)[column_name] can cause truncation error when the column with nchar(10)
data type.
If I have something misunderstood, please provide us more information about the issue. If possible, provide us some screenshots about the package design, error message, expression and column information. So that we can make further analysis and help you
out.
Thanks,
Katherine Xiong
Katherine Xiong
TechNet Community Support