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Comment by jlizzle30 | Hacker News Reader

I've been thinking about prototyping a Firebase clone that uses a relational database and SQL syntax. Instead of subscribing to "nodes" you would subscribe to queries. Anyone know if this exists already?

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Related in a limited fashion:

https://docs.microsoft.com/en-us/dotnet/framework/data/adone...

Then there's this write-up of someone replacing rethinkdb with postgres for live queries - (including a link to some code)

http://blog.sagemath.com/2017/02/09/rethinkdb-vs-postgres.ht...

Have you any plans already of how you will go about this?

How would you (as the DB author) know when a query has updated results?

Something like this:

  subscribe ('SELECT * FROM tableA', callback)

On the initial subscription, 'callback' would be called once for each row in 'tableA', then again when a row is inserted or updated. It would be the same as Firebase in this respect.

No, you as the person writing this new database, not you as the user of the API.

Not OP but I would watch for mutations in the subscribed columns, then test the changed rows on the query's constraints and fire an event if it satisfies them.

I'm sure there is a more clever/efficient way of doing this though, and I can't wait to see how he/she implements it.

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