Access RDS Database by Name like DynamoDB

My resources section looks like below in my serverless file.

       Type: AWS::S3::Bucket
         BucketName: ${self:custom.uploadBucket}
      Type: AWS::RDS::DBInstance
        Engine : mysql
        DBInstanceIdentifier: ${self:custom.databaseName}
        MasterUsername: TestUser123
        MasterUserPassword: TestPass123
        DBInstanceClass : db.m1.small
        AllocatedStorage: '5'
        PubliclyAccessible: true
      DeletionPolicy: Snapshot

I created the DBInstanceIdentifier dynamically based on the stage when I run servleress deploy, like this, serverless deploy --stage dev

I am able to create DynamoDB Tables dynamically and connect to them merely referencing the tablename in my Lambda functions. RDS requires a hostname,username and password. Is there a way to connect to RDS like how DynamoDB works by its database name?

I posted a more detailed question here

AWS supports IAM authentication for MySQL and Aurora

The other option is to set some variables like RDS_USERNAME and RDS_PASSWORD in your serverless.yml then use the variables for MasterUsername and MasterUserPassword and pass them into your Lambda as environment variables.