A distributed database has which of the following advantages over a centralized database?
A. Software cost
B. Software complexity
C. Slow Response
D. Modular growth
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An autonomous homogenous environment is which of the following?
A. The same DBMS is at each node and each DBMS works independently.
B. The same DBMS is at each node and a central DBMS coordinates database access.
C. A different DBMS is at each node and each DBMS works independently.
D. A different DBMS is at each node and a central DBMS coordinates database access.
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A transaction manager is which of the following?
A. Maintains a log of transactions
B. Maintains before and after database images
C. Maintains appropriate concurrency control
D. All of the above
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Location transparency allows for which of the following?
A. Users to treat the data as if it is at one location
B. Programmers to treat the data as if it is at one location
C. Managers to treat the data as if it is at one location
D. All of the above
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A heterogeneous distributed database is which of the following?
A. The same DBMS is used at each location and data are not distributed across all nodes.
B. The same DBMS is used at each location and data are distributed across all nodes.
C. A different DBMS is used at each location and data are not distributed across all nodes.
D. A different DBMS is used at each location and data are distributed across all nodes.
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Some of the columns of a relation are at different sites is which of the following?
A. Data Replication
B. Horizontal Partitioning
C. Vertical Partitioning
D. Horizontal and Vertical Partitioning
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Which of the following is true concerning a global transaction?
A. The required data are at one local site and the distributed DBMS routes requests as necessary.
B. The required data are located in at least one nonlocal site and the distributed DBMS routes requests as necessary.
C. The required data are at one local site and the distributed DBMS passes the request to only the local DBMS.
D. The required data are located in at least one nonlocal site and the distributed DBMS passes the request to only the local DBMS.
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A homogenous distributed database is which of the following?
A. The same DBMS is used at each location and data are not distributed across all nodes.
B. The same DBMS is used at each location and data are distributed across all nodes.
C. A different DBMS is used at each location and data are not distributed across all nodes.
D. A different DBMS is used at each location and data are distributed across all nodes.
Select an option to see the answer and solution.
Replication should be used when which of the following exist?
A. When transmission speeds and capacity in a network prohibit frequent refreshing of large tables.
B. When using many nodes with different operating systems and DBMSs and database designs.
C. The application's data can be somewhat out-of-date.
D. All of the above.
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Storing a separate copy of the database at multiple locations is which of the following?
A. Data Replication
B. Horizontal Partitioning
C. Vertical Partitioning
D. Horizontal and Vertical Partitioning
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A distributed database is which of the following?
A. A single logical database that is spread to multiple locations and is interconnected by a network
B. A loose collection of file that is spread to multiple locations and is interconnected by a network
C. A single logical database that is limited to one location.
D. A loose collection of file that is limited to one location.
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A semijoin is which of the following?
A. Only the joining attributes are sent from one site to another and then all of the rows are returned.
B. All of the attributes are sent from one site to another and then only the required rows are returned.
C. Only the joining attributes are sent from one site to another and then only the required rows are returned.
D. None of the above
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Which of the following is a disadvantage of replication?
A. Reduced network traffic
B. If the database fails at one site, a copy can be located at another site.
C. Each site must have the same storage capacity.
D. Each transaction may proceed without coordination across the network.
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A distributed database can use which of the following strategies?
A. Totally centralized at one location and accessed by many sites
B. Partially or totally replicated across sites
C. Partitioned into segments at different sites
D. All of the above
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Which of the following is not one of the stages in the evolution of distributed DBMS?
A. Unit of work
B. Remote unit of work
C. Distributed unit of Work
D. Distributed request
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With failure transparency, all of the actions of a transaction are committed or none of them are committed.
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Each site (or node) in a distributed system is subject to the same types of failure as in a centralized system.
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Replication may use either synchronous or asynchronous distributed database technologies, although asynchronous technologies are more typical in a replicated environment.
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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.
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With asynchronous technology, if any copy of a data item is updated anywhere on the network, the same update is immediately applied to all other copies or it is aborted.
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