Understanding COMPATIBILITY_LEVEL in SQL Server

I understood that setting a database to a COMPATIBILITY_LEVEL prior to your native one prevented features from being used. However this doesn't seem to be the case. Witness the following SQL script:

CREATE DATABASE Foo
GO
USE Foo
GO
ALTER DATABASE Foo SET COMPATIBILITY_LEVEL = 80
GO

CREATE TABLE Bar
(
    Id UNIQUEIDENTIFIER NOT NULL,
    TestNvc开发者_JAVA技巧Max NVARCHAR (MAX) NOT NULL, -- Arrived in SQL 2005
    TestDateTime2 DATETIME2 (7) NOT NULL -- Arrived in SQL 2008
)
GO

But this table creates perfectly - any ideas? I would have thought some kind of an error message or warning would have been appropriate

Here you can read about the differences between compatibility level 80, 90 and 100. ALTER DATABASE Compatibility Level

Apparently new data types is not affected. I think that compatibility level is there to make SQL Server "behave" like the older version, not prevent you from doing new fancy stuff.

BOL says:

Compatibility level provides only partial backward compatibility with earlier versions of SQL Server.

Also:

New functionality might work under older compatibility levels, but SET options might require adjustments.

I believe that is your case.

I understand this is an old post, but for anyone else who ends up here as I did, more information is always helpful.

It could also be that the new compatibility did not take effect before running the create table statement.

"The new compatibility setting for a database takes effect when a USE Database is issued or a new login is processed with that database as the default database." (https://msdn.microsoft.com/en-us/library/bb510680.aspx)