A logical flaw with function-based CHECK constraints in SQL Server
Limitation of using functions to evaluate multi-row CHECK constraints

Not the model, Bill
Reaction to an InfoWorld report about Bill Gates' views on declarative code and modelling

The nullable uniqueness constraints dilemma (feedback on Microsoft Connect):
Change UNIQUE constraint to allow multiple NULL values
Don't allow nullable columns as part of UNIQUE constraints

SQL Server data types

Microsoft Integration Services vs Informatica PowerCenter feature comparison