Capture Error number of log backup failure - tsql

Question

The below code throws an error when a full backup is missing.
BACKUP LOG [TESTDB] TO DISK = 'C:\DBADMIN\Backup\TESTDB_LOG.BAK'
Msg 4214, Level 16, State 1, Line 4
BACKUP LOG cannot be performed because there is no current database backup.
Msg 3013, Level 16, State 1, Line 4
BACKUP LOG is terminating abnormally.
I am trying to capture the ERROR number of the statement with below code but couldn't capture the error 4214.
BEGIN TRY
BACKUP LOG [TESTDB] TO DISK = 'C:\DBADMIN\Backup\TESTDB_LOG.BAK'
END TRY
BEGIN CATCH
SELECT ERROR_NUMBER() AS 'ERROR_NUMBER';
END CATCH
Output :
ERROR_NUMBER 3013
Please could someone help me to capture the error number 4214

Answer 1

Not sure how important the error number itself is for you, but you could try something like:
DECLARE #inputFile NVARCHAR(100);
DECLARE #Exists int;
SET #inputFile = 'C:\DBADMIN\Backup\TESTDB_LOG.BAK'
EXEC master.dbo.xp_fileexist #inputFile, #Exists OUTPUT
BEGIN TRY
IF #Exists = 1
BACKUP LOG [TESTDB] TO DISK = #inputFile
ELSE
EXEC sys.sp_addmessage #msgnum = 54214,#severity = 16,#msgtext = N'BACKUP LOG cannot be performed because there is no current database backup.',#lang = 'us_english';
RAISERROR (54214,16,1)
END TRY
BEGIN CATCH
SELECT ERROR_NUMBER() AS 'ERROR_NUMBER', ERROR_MESSAGE() as 'ERROR_MESSAGE';
END CATCH
The ELSE statement generates a custom error for you, if the file does not exist. You could do some different action here other than raising an error. Hope that helps.

Answer 2

SQL error 4214 mainly occurs when you have never taken full backup and you are trying to take backup of log only. To resolve this problem, perform full database backup and then attempt to take log backup.