create table sns_notifications (
  type text not null,
  message_id text not null,
  topic_arn text not null,
  message text not null,
  timestamp text not null,
  signature_version text not null,
  signature text not null,
  signing_cert_u_r_l text not null,
  token text,
  subject text,
  subscribe_u_r_l text,
  unsubscribe_u_r_l text
);

comment on column sns_notifications.type is '
  The type of message. For a unsubscribe confirmation, the type is UnsubscribeConfirmation.
';
comment on column sns_notifications.message_id is '
  A Universally Unique Identifier, unique for each message published. For a message that Amazon SNS resends during a retry, the message ID of the original message is used.
';
comment on column sns_notifications.topic_arn is '
  The Amazon Resource Name (ARN) for the topic that this endpoint has been unsubscribed from.
';
comment on column sns_notifications.message is '
  A string that describes the message.
';
comment on column sns_notifications.timestamp is '
  The time (GMT) when the unsubscribe confirmation was sent.
';
comment on column sns_notifications.signature_version is '
  Version of the Amazon SNS signature used.
';
comment on column sns_notifications.signature is '
  Base64-encoded 'SHA1withRSA' signature of the Message, MessageId, Type, Timestamp, and TopicArn values.
';
comment on column sns_notifications.signing_cert_u_r_l is '
  The URL to the certificate that was used to sign the message.
';
comment on column sns_notifications.token is '
  A value you can use with the ConfirmSubscription action to re-confirm the subscription. Alternatively, you can simply visit the SubscribeURL.
';
comment on column sns_notifications.subject is '
  The Subject parameter specified when the notification was published to the topic. Note that this is an optional parameter. If no Subject was specified, then this name/value pair does not appear in this JSON document.
';
comment on column sns_notifications.subscribe_u_r_l is '
  The URL that you must visit in order to re-confirm the subscription. Alternatively, you can instead use the Token with the ConfirmSubscription action to re-confirm the subscription.
';
comment on column sns_notifications.unsubscribe_u_r_l is '
  A URL that you can use to unsubscribe the endpoint from this topic. If you visit this URL, Amazon SNS unsubscribes the endpoint and stops sending notifications to this endpoint.
';