S.no MongoDB OrientDB
1. MongoDB does not support ACID transactions, but MongoDB supports atomic operations. OrientDB supports both ACID transactions and atomic operations.
2. MongoDB has its own language which is based on JSON The query language is fundamentally built on SQL.
3. MongoDB uses B-Tree algorithm for all the indexes. OrientDB helps three different indexing algorithms so that the user can achieve the best performance.
BY Best Interview Question ON 10 Apr 2019