A rule of thumb for choosing indexes for a relational database includes which of the following?
Options: Indexes are more useful on smaller tables., Indexes are more useful for columns that do not appear frequently in the WHERE clause in queries., Do not specify a unique index for the primary key of each table., Be careful indexing attributes that have null values.
Options: (A)Machine-learning involving different techniques (B) The learning algorithmic analyzes the examples on a systematic basis and makes incremental adjustments to the theory that is learned 120 | (C) Learning by generalizing from examples (D) None of these 4
How does a host on an Ethernet LAN know when to transmit after a collision has occurred? In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting. You can improve the CSMA/CD network by adding more hubs. After a collision, the station that detected the collision has first priority to resend the lost data. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.
Options: (A)The conduct of business with the assistance of telecommunications and telecommunications-based tools (B) The conduct of commerce in goods and services, with the assistance of telecommunications and telecommunications-based tools (C) It refers to means whereby sellers can communicate their offerings to potential buyers. (D) None of these
Options: (A)Controls the data exchange between main memory and I/O module. (B) The processor issues I/O command, execute subsequent instructions and interrupt I/O module. (C) The processor issues I/O commands to an I/O module. (D) None of these. 14