data-warehouse

I always thought that databases should be denormalized for read performance, as it is done for OLAP database design, and not exaggerated much further 3NF for OLTP design. PerformanceDBA in various posts, for ex., in Performance of different aproaches to time-based data defends the paradigm that database should be always well-designed by normalization to 5NF and 6NF (Normal Form). Have I understood it correctly (and what had I understood correctly)? What's wrong with the traditional denormalization approach/paradigm design of OLAP databases (below 3NF) and the advice that 3NF is enough for most

For my data warehouse, I am creating a calendar table as follows: SET NOCOUNT ON DROP Table dbo.Calendar GO Create Table dbo.Calendar ( CalendarId Integer NOT NULL, DateValue Date NOT NULL, DayNumberOfWeek Integer NOT NULL, NameOfDay VarChar (10) NOT NULL, NameOfMonth VarChar (10) NOT NULL, WeekOfYear Integer NOT NULL, JulianDay Integer NOT NULL, USAIsBankHoliday Bit NOT NULL, USADayName VarChar (100) NULL, ) ALTER TABLE dbo.Calendar ADD CONSTRAINT DF_Calendar_USAIsBankHoliday DEFAULT 0 FOR USAIsBankHoliday GO ALTER TABLE dbo.Calendar ADD CONSTRAINT DF_Calendar_USADayName DEFAULT '' FOR