Not Trusted Foreign Key Constraints are such for which integrity of the underlying data is not guaranteed. This most commonly happens when you perform Bulk Insert into a table that has a FK constraint, or when you disable a FK constraint.
Having not trusted foreign keys can be dangerous for data integrity, because it’s possible to have invalid data in your table (despite the existence of the foreign key). Continue reading Find and fix untrusted Foreign Keys in all databases
Unlike foreign keys, primary keys and unique indexes cannot be “untrusted”. There’s no “NOCHECK” option for unique constraints. The closest there is, is the “ignore_dup_key” option. “Hmm… That sounds interesting”, you must be thinking. But let me stop you right there, buddy. Read this before you go off doing something potentially dangerous… Very, VERY dangerous. But it does NOT mean that you can create such … Continue reading The "IGNORE_DUP_KEY" option in Primary Keys and Unique Indexes