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  • Question

  • what is the data consistency and what is dat integrity...?

    Monday, March 22, 2010 6:53 AM

Answers

  • data consistency means that each user sees a consistent view of the data, including visible changes made by the user's own transactions and transactions of other users.

    data integrity is the assurance that data is consistent, correct, and accessible.

    Monday, March 22, 2010 7:40 AM

All replies

  • what is the data consistency and what is dat integrity ...?


    Data consistency

    Execution of transaction in isolation preserves the consistency of the data. The data value stored in the database must satisfy certain consistency constraints. For example the balance on an account should not fall below $100. The DDL commands provide the facilities to specify such constraints. The database systems check these constraints every- time the database is updated. In general it can be an arbitrary predicate pertaining to the database. To check the consistency of database most of programmer depends on the constraints and these are usually costly to test.

    Consistency
    Consistency is that when a transaction is taking place on a database

    item, then access to it should not be allowed to other users during that transaction.

    Data integrity

    The integrity of data refers to as "whole data at one place". The data is in the form of tables and each table has some attributes. These are the cases where we wish to ensure that a value that appears in one relation for given set of attributes should also appear for a certain set of attributes in another relation (referential integrity). Database modification can cause violation of integrity. When the integrity constraint is violated, the normal procedure rejects the action that has actually caused the violation.

    Monday, March 22, 2010 7:35 AM
  • data consistency means that each user sees a consistent view of the data, including visible changes made by the user's own transactions and transactions of other users.

    data integrity is the assurance that data is consistent, correct, and accessible.

    Monday, March 22, 2010 7:40 AM
  • SJohio, good answer. It probably goes beyond what the user sees into all of the aspects of the data, but definitely a nicely concise way of stating it, even if you used the root word of consistency in the definition of integrity :)
    Louis

    Tuesday, March 23, 2010 5:49 PM