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by freeqaz 2310 days ago
They are tools that solve different problems, imo. In CAP theorem[0] you have 3 groups of DBs.

CA databases: SQL databases that are hard to scale ("partition") but are always consistent and available.

CP databases: MongoDB style databases that are consistent and partition tolerant, but trade availability (sometimes your queries will fail during high load).

AP databases: CouchDB style databases. They are always available and are partition tolerant, but you may be querying stale data.

[0]: https://en.wikipedia.org/wiki/CAP_theorem?wprov=sfla1