Yes it is fixed at design time but i want not to execute once ! I think every week i get a new file and i want to create a job to start the transformation to import the data. I want to guarantee that nothing has changed since the last time. For every week and every file create a new transformation or update the transformation (preview rows, data field names ) cost a lot of time that i think isn't neccessary.
Maybe the file header and data change every half year.
So i need a Data Validator or anything else.