Duplicate primary key in bulk insert after truncate in SQL Server 2008?

I'm using SSIS to dump data from my SQL Server 2008 prod database to flat files and then using bulk insert to load those flat files into the SQL Server 2008 dev database. The SSIS package is running a TRUNCATE TABLE statement before the bulk insert, but when I run it I still get this error: "The statement has been terminated. Violation of PRIMARY KEY constraint. Cannot insert duplicate key." Why would there be a duplicate key after a truncate? Is there something more I need to do to clear the primary keys before the bulk insert?

If you've truncated the table, then a primary key violation must be coming from duplicate data in the file. Try bulk inserting into a new table, without the PK constraint, and then check the table for duplicates (probably easier than writing some tool or script to parse the file directly). You can create a mimic table that won't have constraints this way:

SELECT * INTO dbo.new_bulk_source
  FROM dbo.old_source
  WHERE 1 = 0;

Then change your package to reference this table, do the insert, then run:

SELECT key FROM dbo.new_bulk_source
  GROUP BY key
  HAVING COUNT(*) > 1;

I bet a donut the call is coming from inside the house (or the truncate is not succeeding).

StackExchange Database Administrators Q#21972, answer score: 5