Apache Cassandra is designed as an eventually consistent database that allows per-operation tradeoff between consistency and availability through tunable consistency levels. However, this approach does not support multi-shard ACID transactions, and its features such as quorum writes/reads, lightweight transactions, and secondary indexes are not suitable for achieving single-key ACID guarantees. Instead, these features can lead to poor performance and inconsistent data. Cassandra's eventual consistency model is based on a BASE paradigm that prioritizes availability over strong consistency, which means it sacrifices some level of consistency to achieve higher availability. This approach is fundamentally different from traditional database systems like Oracle or IBM DB2 that follow the ACID paradigm, which guarantees atomicity, consistency, isolation, and durability. For use cases requiring strong consistency, low latency, and high density, newer databases like YugabyteDB offer a more transactional approach that solves the problems associated with Cassandra's eventual consistency model.