Q.1
Data replication is favored where most process requests are read-only and where the data are relatively static.
Q.2
The cost to perform a snapshot refresh may depend on whether the snapshot is simple or complex.
Q.3
The semijoin approach saves network traffic.
Q.4
In a semijoin, only the joining attribute is sent from one site to another, and then only the required rows are returned.
Q.5
The problem of concurrency control is more complex in a distributed database.
Q.6
Databases that are stored on computers at multiple locations and are not interconnected by a network are known as distributed databases.
Q.7
An increasingly popular option for data distribution as well as for fault tolerance of any database is to store a separate copy of the database at each of two or more sites.
Q.8
Asynchronous technology can result in unsatisfactorily slow response time because the distributed DBMS is spending considerable time checking that an update is accurately and completely propagated across the network.
Q.9
A distributed unit of work allows various statements within a unit of work to refer to multiple remote DBMS locations.
Q.10
The purpose of timestamping is to avoid the use of locks.
Q.11
With failure transparency, all of the actions of a transaction are committed or none of them are committed.
Q.12
Each site (or node) in a distributed system is subject to the same types of failure as in a centralized system.
Q.13
A distributed database is which of the following?
Q.14
A semijoin is which of the following?
Q.15
Which of the following is a disadvantage of replication?
Q.16
Some of the columns of a relation are at different sites is which of the following?
Q.17
Which of the following is true concerning a global transaction?
Q.18
Replication may use either synchronous or asynchronous distributed database technologies, although asynchronous technologies are more typical in a replicated environment.
Q.19
Synchronization for pull replication is less disruptive and occurs only when needed by each site, not when a central master site thinks it is best to update.
Q.20
A distributed database can use which of the following strategies?
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