1. An apparatus for atomic transactions in a NoSQL database, the apparatus comprising: a processor; and one or more stored sequences of instructions which, when executed by the processor, cause the processor to implement the steps of: determining whether write claim data for a first data item in a NoSQL database includes a first previous transaction identifier included in last commit data for the first data item; writing a pending transaction identifier to the write claim data for the first data item in response to a determination that the write claim data for the first data item includes the first previous transaction identifier included in the last commit data for the first data item; writing the pending transaction identifier and a pending commit identifier to the last commit data for the first data item; writing a first value associated with a pending transaction to the first data item; and aborting the pending transaction in response to a determination that the write claim data for the first data item does not include the first previous transaction identifier included in the last commit data for the first data item.