Compare SEQUENCE cache size, restart gaps, rollback gaps, and insert throughput with CACHE 50, CACHE 1000, and NO CACHE.
External Profiles: Keep Email Out of the Key
External profiles need a stable scoped identity key. Keep mutable email values separate and reject duplicate identities.
SQL SERVER – How to ALTER CONSTRAINT
Can you ALTER CONSTRAINT in SQL Server? No. The only way to change a constraint is to drop it and create it again, and here is the script for that.
SQL SERVER – Prevent Constraint to Allow NULL
Why does a CHECK constraint allow NULL? A reader thought it was a bug. I show why it happens and how to write the constraint so NULL is rejected too.
GTIN-13 Check Digits: Validate the Final Digit in a CHECK Constraint
A GTIN-13 check digit validates a weighted checksum, not product identity. Test complete ASCII input, leading zeros and the final digit in a CHECK constraint, then see why some digit swaps still pass.
Turning a Comma-Separated Column Into a Proper Child Table
A list stuffed in one column makes every search a guess. Split it, clean it and move it into a child table, then check the result before you drop anything.
Resumable ADD CONSTRAINT in SQL Server 2022: Pausing a Primary Key Build
Use resumable ADD CONSTRAINT in SQL Server 2022 to pause a key build, inspect progress, resume safely, and understand abort behavior.