Вот пара методов тестирования на наличие ДМК.
Обратите внимание, что в столбце [is_master_key_encrypted_by_server] в sys.databases может отображаться 0, но DMK существует и удален из-за шифрования SMK.
Надеюсь, это поможет.
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-- Test for existence of a DMK. If it does not exist, then create it.
-- Method 1:
IF (SELECT COUNT(*) FROM sys.symmetric_keys WHERE name LIKE '%DatabaseMasterKey%') = 0
BEGIN
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'ljlLKJjs$2@l23je'
END
-- Method 2:
IF NOT EXISTS (SELECT * FROM sys.symmetric_keys WHERE name LIKE '%DatabaseMasterKey%')
BEGIN
SELECT 'DMK does not exist'
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'ljlLKJjs$2@l23je'
END
ELSE
BEGIN
SELECT 'DMK exists'
END
-- Demo showing that is_master_key_encrypted_by_server in sys.databases does not show whether the DMK exists or not.
DROP MASTER KEY
GO
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'ljlLKJjs$2@l23je'
GO
SELECT is_master_key_encrypted_by_server, name
FROM sys.databases
WHERE name = 'GalaxianTest1'
--> is_master_key_encrypted_by_server name
--> 1 GalaxianTest1
USE GalaxianTest1
GO
-- This command causes the DMK to not be encrypted by the SMK.
ALTER MASTER KEY DROP ENCRYPTION BY SERVICE MASTER KEY
-- This command now shows 0, although the DMK still exists.
SELECT is_master_key_encrypted_by_server, name
FROM sys.databases
WHERE name = 'GalaxianTest1'
--> is_master_key_encrypted_by_server name
--> 0 GalaxianTest1
-- Try creating a new DMK. This will error because the DMK still exists.
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'ljlLKJjs$2@l23je'
GO
--> Error: There is already a master key in the database. Please drop it before performing this statement.
DROP MASTER KEY
GO
--> Command(s) completed successfully.
SELECT is_master_key_encrypted_by_server, name
FROM sys.databases
WHERE name = 'GalaxianTest1'
--> is_master_key_encrypted_by_server name
--> 0 GalaxianTest1
-- Note: this is the same message as above when the DMK existed, but had been dropped from encryption by service master key.