the error message is obvious. Your SSIS package has a mapping between RecordID column from source which is of length 255 to RecType field which just has length of 1. This can be a potential cause for value truncation which is what SSIS complains about.
If source is a flat file it usually takes length as 255 by default for text data. So the solutions are 1. Add a derived column in between source and destination (flat file source and oledb table) and add an expression to take only first character. You should do this only if you're sure the source field will have only one character data always 2. Another way is to go to advanced properties of flat file and chage it as per your business rule (ie if you're certain it can contain only 1 character make it 1
I wish it were so easy. I had already changed the Flat file Connection by setting the correct Input Column Width for each column. And the Preview window shos everything correctly, all columns. No columns are defined as length 255. I don't know why I'm getting Validation warning. Data Flow Task: Truncation may occur due to inserting data from data flow column "RecordID" with a length of 255 to database column "RecType" with a length of 1.