Take the tour ×  From Wikipedia:  Consistency (ACID)  "In
database systems, a consistent transaction is one that does not
violate any integrity constraints during its execution. If a
transaction leaves the database in an illegal state, it is
aborted and an error is reported."  If a noSql database doesn't
have a concept of integrity constraints, then how are they
claiming to be ACID compliant? It strikes me that they think of
consistency as something else (perhaps sameness across a
cluster), or that without constraints it can't violate any and
so they pass by default.  share|improve this question Many NoSQL
databases are not claiming to be fully acid-compliant. – 
Philipp Feb 25 at 12:10 They replace the "C" (Consistency) with
another definition of consistency like Eventual Consistency
(sometimes in the future will the modification be visible in all
parts of the cluster and conflicts needs to be resolved along
the way) or Local Consistency (the consistency is assured only
within one single node and not through