A database transaction, by definition, must be atomic (it must either be complete in its entirety or have no effect whatsoever), consistent (it must conform to existing constraints in the database), isolated (it must not affect other transactions) and durable (it must get written to persistent storage).
A single transaction consists of one or more independent units of work, each reading and/or writing information to a database or other data store.
When this happens it is often important to ensure that all such processing leaves the database or data store in a consistent state.
Transactions ensure that the database is always in a consistent state, even in the event of concurrent updates and failures.
The highest isolation level is serializability, which guarantees that the effect of concurrent transactions is equivalent to their serial (i.e. sequential) execution.
Most modern[update] relational database management systems support transactions.
NoSQL databases prioritize scalability along with supporting transactions in order to guarantee data consistency in the event of concurrent updates and accesses.
At the lowest level (READ UNCOMMITTED), which may occasionally be used to ensure high concurrency, such changes will be immediately visible.
Object databases comprise variable-sized blobs, possibly serializable or incorporating a mime-type.
Moreover, the integration of Storage as a Service (StaaS) within these environments is crucial, as it offers a virtually infinite pool of storage resources, accommodating a range of cloud-based data store classes with varying availability, scalability, and ACID properties.
This integration is essential for achieving higher availability, lower response time, and cost efficiency in data-intensive applications deployed across cloud-based data stores.