These changes might cause deployment errors or data loss.

In SQL Source Control there will be a triangle with an exclamation mark in it alerting you "These changes might cause deployment errors or data loss. Make sure a migration script covers the change." This likely means you'll need a migration script. There will be a loud button for creating the migration script at the "Commit" tab if you select the angry line item. Remember to doctor up the suggested script to replace existing null values with zeros or whatever. Make migration scripts right before you check in as you cannot gracefully have the other changes afterwards.