Data consistency
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Data consistency summarizes the validity, accuracy, usability and integrity of related data between applications and across the IT enterprise. This ensures that each user observes a consistent view of the data, including visible changes made by the user's own transactions and transactions of other users or processes. Data Consistency problems may arise at any time but are frequently introduced during or following recovery situations when backup copies of the data are used in place of the original data.
Various kinds of data consistency have been identified. These include Application Consistency , Transaction Consistency and Point-in-Time (PiT) Consistency.
Point in Time Consistency: Data is Point in Time consistent if all of the interrelated data components (either a group of data sets or a set of logical volumes) are as they were at any single instant in time.
Transaction Consistency: A transaction is a logical unit of work that may include any number of file or database updates.
Application Consistency: Application Consistency is similar to Transaction consistency, but instead of data consistency within the scope of a single transaction, data must be consistent within the confines of many different transaction streams from one or more applications.
[edit] Related Information
- See Dependent Write
