Regarding those 3 error messages:
The first could be due to the Asymmetric Key already existing, but under a different name. Keys and Certificates need to be unique in terms of their public key, not just the name (though that obviously needs to be unique as well). Each Key and Certificate has a hash of the public key which is referred to as the "thumbprint". The thumbprints of existing Keys / Certificates are checked when creating a new one and will prevent the creation, even of a differently named Key / Certificate, if the thumbprint already exists. That is what the error message means by "or this asymmetric key already has been added to the database".
OR:
It could mean that a different Asymmetric Key (i.e. different "thumbprint") exists in master, but with the name AProjectKey
- Because you couldn't create the same key under a different name, no Asymmetric Key exists with that new name, hence you can't create a Login from it (since, again, the
CREATE ASYMMETRIC KEY statement failed).
- Because you couldn't create the Login, it doesn't exist to be granted any permissions.
Error # 2 helps narrow down the issue. If Error # 1 was caused by an existing Asymmetric Key having the same name but different "thumbprint", then you either would have been able to create the Login (if it did not already exist), or you would have gotten an error stating that the Login (i.e. "server principal") already exists. But the error is that an Asymmetric Key by that name cannot be found. This should mean that the Asymmetric Key itself does already exist, but under a different name. You can see what Asymmetric Keys have been created by executing the following:
SELECT * FROM sys.asymmetric_keys;
But that doesn't tell you which one came from that Assembly (or an Assembly signed with the same Strong Name Key used to sign this one). For that you need to know the "thumbprint", and for that you need to open a Command Prompt (preferably a "Developer Command Prompt" which Visual Studio sets up when installed, as it has the correct path set up upon opening it). Then, run the following:
CD /D E:\sqldlls\
sn -T TableFile.dll
You should see:
Public key token is XXXXXXXXXXXXXXXX
Copy and paste that XXXXX "token" (i.e. thumbprint) into the following query:
SELECT ak.[name], ak.[sid]
FROM sys.asymmetric_keys ak
WHERE ak.[thumbprint] = 0x{XXXXXXXXXXXXXXXX}; -- remove the { and }
Assuming that you get a row returned, we need to see if the Login exists. Simply trying to create a Login from the Asymmetric Key won't get us the Login's name if it does exist since you can only have 1 Login created per Key / Certificate, and the error message only reports back the name you are trying to create as the one that already exists, even though it can be a different name for the same Key. So, take the SID from the returned row and paste it in the following query:
SELECT sp.*
FROM sys.server_principals sp
WHERE sp.[sid] = 0x{SID_from_sys_asymmetric_keys}; -- remove the { and }
If no row is returned then you should create a Login from that Asymmetric Key.
At this point a Login should exist, so grant it the UNSAFE ASSEMBLY permission.
Now try creating the Assembly again.
