Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
10 Cards in this Set
- Front
- Back
|
What is a distributed database management system?
|
Database are distributed over multiple physically independent locations supported by a communications network.q
|
|
|
What is the difference between distributed processing and distributed database?
|
Distributed Processing - distributed over multiple physically independent sites, connected via a communication network
Distributed Database -Databases are distributed over multiple site fragments. |
|
|
Name key components of a distributed database system.
|
Nodes / WorkStation
Hardware / Software Transition Processor |
|
|
Briefly explain three levels of data and process distribution.
-Single site processing, single site data (SPSD) -Multi site processing, single site data (MPSD) -Multi site processing, multi site data (MPMD) |
In the single-site processing, single-site data (SPSD) scenario, all processing is done on a single host computer, and all data are stored on the host computer's local disk system
Multi site processing, single site data scenario describes a fully distributed DBMS with support for multiple data processors and all data are stored on the host computer's local disk system The multiple-site processing, multiple-site data (MPMD) scenario describes a fully distributed DBMS with support for multiple data processors and transaction processors at multiple sites. |
|
|
Briefly explain failure transparency, performance transparency, and heterogeneity transparency.
|
Failure Transparency - In a distributed system, failure transparency refers to the extent to which errors and subsequent recoveries of hosts and services within the system are invisible to users and applications.
Performance transparency is accomplished when the DDBMS allows the database to perform as if it were a centralized database. |
|
|
What is distribution transparency? Briefly explain fragmentation transparency, location transparency, and local mapping transparency.
|
Distribution Transparency is where a database system is distributed among different regions, but the user only sees the results. Fragmentation transparency means that objects are accessed without knowledge of any possible fragmentation.
|
|
|
What is transaction transparency.
|
Highest level of transparency; End-user does not know that databases are partitioned
|
|
|
Briefly explain remote request, remote transaction, distributed transaction, and distributed request.
|
Remote request – single SQL statement accesses data from single remote database
Remote transaction – accesses data at single remote site Distributed Transaction – requests data from several different remote sites on network Distributed request – Single SQL statement references data at several DP sites. |
|
|
What is the purpose of two-phase commit protocol? Briefly explain working of the two-phase commit protocol.
|
End user must specify both fragment names and locations.
|
|
|
Briefly explain horizontal, vertical, and mixed fragmentation techniques.
|
• Horizontal fragmentation -Division of a relation into subsets (fragments) of tuples (rows)
• Vertical fragmentation -Division of a relation into attribute (column) subsets • Mixed fragmentation -Combination of horizontal and vertical strategies (split with horizontal first then split again with vertical) |
