can we create database user name start with underscore(_) in aws Redshift?
No,its not allowed in IAM database user with Single sign on,you should create the database name starting with character.
DbUser parameter must begin with a letter, contain only alphanumeric characters, underscore ('_'), plus sign ('+'), dot ('.'), at ('@'), or hyphen ('-'), and be less than 128 characters. (Service: AmazonRedshift; Status Code: 400; Error Code: InvalidParameterValue
