Mercury is the only common metal which is liquid at ordinary temperatures. Mercury is sometimes called quicksilver. It is a heavy, silvery-white liquid metal. It is a rather poor conductor of heat if compared with other metals but it is a fair conductor of electricity. It alloys easily with many metals, such as gold, silver, and tin. These alloys are called amalgams.
describe big data, so that you can speak intelligently about it when asked. So probably the main thing to recognize is this notion of the three V's of big data, which are volume, velocity and variety.
Three levels of Data Abstraction 1  â. Physical level: The lowest level of abstraction describes how the data is stored. 2  Logical level: Describes what data is stored in the database and what relationship is among that data. 3  View level: The highest level of database describes only part of the database.