Ubuntu is an open-source operating system (OS) based on the Debian GNU/Linux distribution. Ubuntu incorporates all the features of a Unix OS with an added customizable GUI, which makes it popular in universities and research organizations. Ubuntu is primarily designed to be used on personal computers, although a server editions does also exist....
A database guarantees the following four properties to ensure database reliability, as follows:
Atomicity: A database follows the all or nothing rule, i.e., the database considers all transaction operations as one whole unit or atom. Thus, when a database processes a transaction, it is either fully completed or not executed at all.
Consistency: Ensures that only valid data following all rules and constraints is written in the database. When a transaction results in invalid data, the database reverts to its previous state, which abides by all customary rules and constraints.
Isolation: Ensures that transactions are securely and independently processed at the same time without interference, but it does not ensure the order of transactions. For example, user A withdraws $100 and user B withdraws $250 from user Z’s account, which has a balance of $1000. Since both A and B draw from Z’s account, one of the users is required to wait until the other user transaction is completed, avoiding inconsistent data. If B is required to wait, then B must wait until A’s transaction is completed, and Z’s account balance changes to $900. Now, B can withdraw $250 from this $900 balance.
Durability: In the above example, user B may withdraw $100 only after user A’s transaction is completed and is updated in the database. If the system fails before A’s transaction is logged in the database, A cannot withdraw any money, and Z’s account returns to its previous consistent state.
Read More »
Join 138,000+ IT pros on our weekly newsletter
Home | Advertising Info | Write for Us | About | Contact Us
2010 - 2015
Partner Sites :