alt Hacker NewsIt's all about tradeoffs. Same reason there are so many kinds of wheeled transport and so many kinds of bridges.
There's no single set of requirements and desired properties that people have for databases.
What queries does it accept? How does it persist data? How does it manage replication and partitioning across multiple servers? Are questions with many answers and the right one varies by application.
> What queries does it accept? How does it persist data? How does it manage replication and partitioning across multiple servers? Are questions with many answers and the right one varies by application.
nothing prevents to build single database which would cover all such answers. Its engineering, funding and distribution problems: no-one built it yet.