Can somebody help me how to send Notifications using Azure SQL Server ?
Lets say I want to create an Application where the user adds, updates, or deletes a schedule .
If the scheduler runs and finds that it has to send notifications for a particular time, say 6:00 pm . I was wondering if there is any way I can use SQL Server so it can send the notification when called by the scheduled job. ?
I believe, it is not possible with the SQL Azure. In SQL Server, you have Query Notifications. If you want to use SQL Azure, then i would offer you to implement the notifications functionality in your own application. So, application, when making the changes to the database, sends the notification as well. Somehow, for example, using Azure Queues - with the information about columns updated.
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Looking for some help on an application design. I am using spring framework and hosting application in AWS.
I am working on an enterprise Java Web application that is suppose to handle events when their trigger time is reached. For example, consumers can set an event to begin on 12/20/22 at 07:35 AM, and system is suppose to send a notification when that time is reached.
I can store these events in a database along with their trigger time and setup a Spring scheduler (#Scheduler) to run every minute and process events whose trigger time is reached. My only concern with this approach is, there could be hundreds/thousands of event to trigger at any minute, and it cannot be processed within one minute.
Is there any alternate way to design this? I don't know if Spring offers a feature where I could create these Event, and Frameworks trigger these events when trigger time is reached. In that way, I can stay away from managing Scheduling and Triggering part.
I am using AWS to host this applications, so another option I'm thinking towards is creating an AWS lambda for every such Event, and let AWS manage the triggering part. In that way, I can stay away from managing the triggers.
Let me know your views? Or If you came across similar problems and how you resolved that?
You can consider using spring-cloud-dataflow to manage this as tasks and streams.
You create a custom batch application that will use #Scheduled to check the your database when events are dure and then send events to a stream. You can use Spring Integration APIs to interact with RabbitMQ or Kafka topics.
The event should contain enough information needed to process the event.
You then have a stream application that produces the content and send via email or pass it on to a separate stream app that sends the email.
https://dataflow.spring.io/docs/stream-developer-guides/programming-models/
The flow will look something like:
:mail_events | message-processor | message-sender
You will configure property for mail_events to match the topic created and configured for you mail-event-batch application.
You can use Spring Cloud Data Flow to manage the mail-event-batch application as well.
You can scale each application https://dataflow.spring.io/docs/recipes/scaling/
I've been thinking about how to design a system that supports user created scheduled alerts. My problem is once the alerts are created and inserted into a database, I don't know what the best way to go about scheduling those alerts. Polling the database to see which alerts need to go out next doesn't seem entirely right to me.
What are some ways this could be handled on a scale where say a million users could create their own custom alerts like change baby diaper at 3pm everyday?
This problem is very suitable for cloud platforms. For example, you could use GCP Cloud Scheduler to invoke a cloud function when the alert is supposed to be sent out. The cloud function then calls some API to alert the user.
If cloud platforms are not an option, you could have your application spawn a new thread when an alert is created, and sleep that thread for a certain duration. When it wakes up, it sends the alert. Less elegant and less scalable than the first solution, but it would still work.
We have a microservice which is developed using spring boot. couple of the functionalities it implements is
1) A scheduler that triggers, at a specified time, a file download using webhdfs and process it and once the data is processed, it will send an email to users with the data process summary.
2) Read messages from kafka and once the data is read, send an email to users.
We are now planning to make this application high available either in Active-Active or Active-passive set up. The problem we are facing now is if both the instances of the application are running then both of them will try to download the file/read the data from kafka, process it and send emails. How can this be avoided? I mean to ensure that only one instance triggers the download and process it ?
Please let me know if there is known solution for this kind of scenarios as this seems to be a common scenario in most of the projects? Is master-slave/leader election approach a correct solution?
Thanks
Let the service download that file, extract the information and publish them via kafka.
Check beforehand if the information was already processed by querying kafka or a local DB.
You also could publish an DataProcessed-Event that triggers the EmailService, that sends the corresponding E-Mail.
I have no knowledge on Oracle EBS and Oracle Alert mechanism.
My understanding is that Oracle Alert works just like database trigger.
Will Oracle Alert fire when database updates/inserts happen from the back-end?
We have observed alert is only firing for transactions front end and not running for back-end updates?
Is it guaranteed that just like a Trigger, EBS Alert will fire on every update to the record?
My understanding is that Oracle Alert works just like database trigger.
Yes, it is somewhat like a database trigger created from the Front-End Application. To explain further, there are two types of Oracle Alerts, Periodic and Event Alerts.
Periodic Alerts are alerts have a specific schedule and run according to a set period and time.
Event Alerts are alerts that only send notifications whenever inserts or updates have been performed on a table from the Front-End Application.
Take note that for Event Alerts, the triggering table must be setup in Oracle EBS' Application Object Library (called an Application Table).
Will Oracle Alert fire when database updates/inserts happen from the backend?
No. Taking this line from Krishna Reddy:
Oracle Alerts can only be triggered from an application that has been
registered in Oracle Applications. Alerts cannot be triggered via SQL
updates or deletes to an Alert activated trigger.
To add more context, Oracle Alert is a simple and efficient way to give you an immediate view of the critical activities in your Oracle Application. It helps Business Users / Administrators be on top of important or unusual business events you need to know about via E-Mail. It can also automate a process depending on the user’s response.
Some weaknesses and limitations though, is that Oracle Alert cannot process rows up to more than around 50, and its Report Layout has a text-based design and does not support HTML. Also, the text width is also limited.
Check out the Oracle documentation and this good article about Oracle Alerts.
So what I need is a kind of a push and pull web service mechanism; Certain devices will be sending data to my parse backend and some others should be able to receive the newly added data as it's being added. Think of it as a restaurant environment where customers send their order via their phones and the restaurant manager receives the orders on his pc real time.
I know I can use push notifications but I want to target specific users (in this case the manager alone). I guess I can have a specific push notification channel in which only the manager is added, but I am not sure if I can send proper json data in bulk or just simple strings. Maybe there's a smarter way of going about it.
Any suggestions?
Many thanks,
Polis
You can use the Parse Cloud for this purposes. So certain devices (you can differentiate in cloud or in client side) can call the cloud method. The called cloud method can make http request to your server (manager pc real time). From now on your server side can deliver coming message to your manager in real time. In this solution, I assume that you have your own server for web users (like manager) and mobile application for client user (customers).
Hope this can give you an idea. Regards.
You can use Push notification for this purpose. In my opinion that would be your best option.
When registering for push notification on client side, you can set a column owner to user pointer. Now when sending push notification from one user to another you can query the Installation class for other user's pointer. You can send push notification either from client side or writing cloud code for afterSave trigger. Cloud code is a better option.
The downside of this approach is that if other user did not allow push notifications then this would fail. The second user would still be able to get the data when they open the app, but won't get push notifications.
***I built a chat app using this approach on Parse.com
You don't need a complicated channel setup, before you save your installation, do a line like this:
[installation setObject:[PFUser currentUser] forKey:#"owner"];
[installation saveInBackground]; // ... completion or whatever
Then, just query:
PFQuery *installationQuery = [PFInstallation query];
[installationQuery whereKey:#"owner" equal:userImLookingFor];
Then, it's like PFPush w/ query or something.
(I'm typing from memory, so some of these might need to be slightly tweaked)