Distributed Databases A semijoin is which of the following? Only the joining 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. 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 all of the rows are returned. Only the joining 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. 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 all of the rows are returned. ANSWER DOWNLOAD EXAMIANS APP
Distributed Databases Data replication is favored where most process requests are read-only and where the data are relatively static. True False True False ANSWER DOWNLOAD EXAMIANS APP
Distributed Databases A transaction manager is which of the following? All of these Maintains a log of transactions Maintains before and after database images Maintains appropriate concurrency control All of these Maintains a log of transactions Maintains before and after database images Maintains appropriate concurrency control ANSWER DOWNLOAD EXAMIANS APP
Distributed Databases The cost to perform a snapshot refresh may depend on whether the snapshot is simple or complex. True False True False ANSWER DOWNLOAD EXAMIANS APP
Distributed Databases The semijoin approach saves network traffic. True False True False ANSWER DOWNLOAD EXAMIANS APP
Distributed Databases 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 False True ANSWER DOWNLOAD EXAMIANS APP