Command Query Responsibility Segregation

That is a brilliant mitigation strategy.

Now, the text introduces CQRS, Command Query Responsibility Segregation.

This pattern feels like opening Pandora's box.

It is profound architectural shift.

CQRS acknowledges that at an extreme scale, the data model optimized for complex transactional writes, the commands, is fundamentally incompatible with the data model optimized for blazing fast reads, the queries.

Give me a concrete scenario where this is necessary, because maintaining two entirely separate data models sounds like an operational nightmare.

Think about a massive e-commerce platform's order system.

But what about the user's order history page or the customer support dashboard? Those are read-heavy operations that just need a flat, denormalized view of the order.

Okay.

CQRS, I didn't know much about this a year ago, so I don't expect you to.

Let me break this down for you because it's quite a mouthful.

CQRS is when you segregate the responsibility between your queries... which are your reads and your command, so your writes.

So in a traditional request, request goes to the server, server processes it, generates some HTML or output, sends that back, browser does something with it, request is done.

With CQRS, we tend to open a connection on page load.

And that connection is going to remain open for a longer amount of time.

That's going to be our read or our query.

So it should be a query, a read.

So it makes sense in terms of like CQRS where you're querying as opposed to making any changes or running any commands.

And somebody brought it up in terms of an inline validation example.

We were using post.

So from your application, you just say query 42, run that and you can get the result back or you can stream the result back as well.

So you can open a live query, which remains open for the duration of that request, which means you can just listen to stuff going on in the database and So anybody who's familiar with using long-lived SSE connections in Datastar will well know that this is going to be a perfect match for those types of applications.

Anyone who's using CQRS and doing Fatmort, for example.

everything becomes much, much easier.