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Transitive Data Skew
Data synchronization is the process of establishing consistency between source and target data stores, and the continuous harmonization of the data over time. It is fundamental to a wide variety of applications, including file synchronization and mobile device synchronization. Data synchronization can also be useful in encryption for synchronizing public key servers. File-based solutions There are tools available for file synchronization, version control ( CVS, Subversion, etc.), distributed filesystems ( Coda, etc.), and mirroring (rsync, etc.), in that all these attempt to keep sets of files synchronized. However, only version control and file synchronization tools can deal with modifications to more than one copy of the files. * File synchronization is commonly used for home backups on external hard drives or updating for transport on USB flash drives. The automatic process prevents copying already identical files, thus can save considerable time relative to a manual copy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consistency (database Systems)
In database systems, consistency (or correctness) refers to the requirement that any given database transaction must change affected data only in allowed ways. Any data written to the database must be valid according to all defined rules, including constraints, cascades, triggers, and any combination thereof. This does not guarantee correctness of the transaction in all ways the application programmer might have wanted (that is the responsibility of application-level code) but merely that any programming errors cannot result in the violation of any defined database constraints.C. J. Date, "SQL and Relational Theory: How to Write Accurate SQL Code 2nd edition", ''O'reilly Media, Inc.'', 2012, pg. 180. Consistency can also be understood as after a successful write, update or delete of a Record, any read request immediately receives the latest value of the Record. As an ACID guarantee Consistency is one of the four guarantees that define ACID transactions; however, significant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |