Question

I’m writing an web application for users who need to be able to receive notices from administrators when they login. These notices should be displayed on their dashboard.

Once a user has read a message, they can dismiss it. New users should obviously not be shown messages before they were created.

I’m having two problems with designing the schema:

1. How do I identify that a user has “dismissed” a message?
2. How do new users only see messages after they’ve been created?

Here’s the table for notifications:

CREATE TABLE [dbo].[Notification] 
(
  [Id] [int] IDENTITY(1,1) NOT NULL,
  [Message] [varchar](max) NOT NULL,
  [DateCreated] [datetime] NOT NULL,
  [CreatedById] [int] NOT NULL
)

For #1, I was thinking of creating a table (DismissedNotification_User) that would map between a Notification.Id and a User.Id. If a pair exists, then the user dismissed that notification. However, I’m not sure if this is the best approach (not in vs a left join)?

For #2, the easiest approach that I see is by adding a DateCreated column to users and when adding a condition onto #1 (where [DateCreated] >= [User].DateCreated).

I don’t want cookies involved because that really adds unnecessary weight to the application.

Answer 1

I would say that your own solutions for #1 and #2 here seem fine.

The link table to represent a ‘dismissed’ notification makes sense otherwise you end up having to create one row per user up front, to represent a notification as opposed to one notification record.

I think also for #2, having a created date for the notification and user would be a sensible option too. The other suggestions to use a ‘dismissed’ column would not enable you to only display notification AFTER a user was created if you’re reliant on the option of a linked table as you would end up with all notifications, not just those since the user existed.