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. True False TRUE ANSWER : ? YOUR ANSWER : ?
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. False True TRUE ANSWER : ? YOUR ANSWER : ?
A distributed database is which of the following? A loose collection of file that is spread to multiple locations and is interconnected by a network A single logical database that is spread to multiple locations and is interconnected by a network A loose collection of file that is limited to one location. A single logical database that is limited to one location. TRUE ANSWER : ? YOUR ANSWER : ?
An autonomous homogenous environment is which of the following? The same DBMS is at each node and each DBMS works independently. A different DBMS is at each node and each DBMS works independently. A different DBMS is at each node and a central DBMS coordinates database access. The same DBMS is at each node and a central DBMS coordinates database access. TRUE ANSWER : ? YOUR ANSWER : ?
A transaction manager is which of the following? All of these Maintains before and after database images Maintains a log of transactions Maintains appropriate concurrency control TRUE ANSWER : ? YOUR ANSWER : ?
Replication should be used when which of the following exist? When using many nodes with different operating systems and DBMSs and database designs. The application's data can be somewhat out-of-date. When transmission speeds and capacity in a network prohibit frequent refreshing of large tables. All of these TRUE ANSWER : ? YOUR ANSWER : ?
A semijoin is which of the following? All of the attributes are sent from one site to another and then only the required rows are returned. All of the attributes are sent from one site to another and then only the required rows are returned. Only the joining attributes are sent from one site to another and then only the required rows are returned. Only the joining attributes are sent from one site to another and then all of the rows are returned. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is a disadvantage of replication? Each transaction may proceed without coordination across the network. Reduced network traffic Each site must have the same storage capacity. If the database fails at one site, a copy can be located at another site. TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following is not one of the stages in the evolution of distributed DBMS? Unit of work Distributed request Remote unit of work Distributed unit of Work TRUE ANSWER : ? YOUR ANSWER : ?