How to identify "special principal" in sys catalogs

Question

Is there a property to which can be used to identify "special principals" in sys catalogs?
I have trouble deploying databases using visual studio database edition with msbuild.
Somehow, objects gets created in the middle of deployment which alter the design and prevent crash deployment.
The solution I found is to remove access to db users to prevent the creation of those objects during the deployment.
Using the following query:
select rolep.name, memp.name from sys.database_role_members rm
JOIN sys.database_principals rolep ON rm.role_principal_id = rolep.principal_id
JOIN sys.database_principals memp ON rm.member_principal_id = memp.principal_id
I can extract all users and then generate calls to sp_droprolemember to remove their access.
Of course, this does not work for the user "dbo" which yields the error
"Msg 15405, Level 11, State 1, Procedure sp_droprolemember, Line 76
Cannot use the special principal 'dbo'."
Aside of relying on the role names, Is there a property which can be used to identify "Special principals"?

Answer 1

You would need to adapt your code to the situation. In many cases, you need to exclude dbo. If you want to drop logins in general, you can use the type column in sys.database_principals, so that you don't attempt to drop logins tied to certificates.
(Unless you want drop them that is.) You should probably also keep principals of which the name start with ##, as they are various built-ins.
Erland Sommarskog, SQL Server MVP, [email protected]