Distributed database transparency features
DDBMS transparency features have the common property of allowing the end user to feel like the database s only user . In other words, the user believes that (s)he is working with centralized DBMS; all complexities of a distributed database are hidden ,or transparent to the user.
The DDBMS transparency features are:
• Distribution transparency ,which allows a distributed database to be treated as a single logical database. If a DDBMS exhibits distribution transparency , the user does not need to know:
- That the data are partitioned _ meaning the table s rows and columns
are split vertically or horizontally and stored among multiple sites.
- That the data can be replicated at several sites.
- The data location.
• Transaction transparency, which allows a transaction to update
data at more than one network site Transaction transparency ensures
that the transaction will be either entirely completed or aborted. Thus,
maintaining database integrity.
• Failure transparency. which ensures that the system will continue
to operate in the event of a node failure. Functions that were lost
because of the failure will be picked up by another network node.
• Performance transparency. which allows the system to perform as if
it were a centralized DBMS. The system will not suffer any performance
degradation due to its use on a network or due to the network s
platform differences. Performance transparency also ensures that
the system will find the most cost-effective path to access remote
data.
• Heterogeneity transparency. Which allows the integration of several
different local DBMSs (relational. network, and hierarchical) under a
common, or global, schema. The DDBMS is responsible for translating
the data requests from the global schema to the local DBMS schema.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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