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在数据库的体系结构中，数据库存储的改变会引起内模式的改变。为使数据库的模式保持不变，而且不必修改应用程序，必须通过改变模式与内模式之间的映象来实现。这样，使数据库具有______。
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Can animals have a sense of humor Sally Blanchard, publisher of a newsletter called the Pet Bird Report, thinks a pet parrot may have pulled her leg. That’s one explanation for the time her African gray parrot, named Bongo Marie, seemed to feign distress at the possible death of an Amazon parrot named Paco. It happened one day when Blanchard was making Cornish game hen for dinner. As Blanchard lifted her knife, the African gray threw back its head and said, "Oh, no! Paco!" Trying not to laugh, Blanchard said, "That’s not Paco," and showed Bongo Marie that the Amazon was alive and well. Mimicking a disappointed tone, Bongo Marie said, "Oh, no," and launched into a hoarse laugh. Was the parrot joking when it seemed to believe the other bird was a goner Did Bongo Marie comprehend Blanchard’s response Studies of African grays have shown that they can understand the meaning of words--for example, that red refers to a color, not just a particular red object. Parrots also enjoy getting a reaction out of humans, and so, whether or not Bongo Marie’s crocodile tears were intentional, the episode was thoroughly satisfying from the parrot’s point of view. In the last sentence, the clause "the episode was...point of view" suggests that Bongo Marie was ______.
Assuming that a constant travel-time budget, geographic constraints and short-term infrastructure constraints persist as fundamental features of global mobility, what long-term results can one expect In high-income regions, (41) North America, our picture suggests that the share of traffic (42) supplied by buses and automobiles will decline as high-speed transport rises sharply. In developing countries, we (43) the strongest increase to be in the shares first for buses and later for automobiles. Globally, these (44) in bus and automobile transport are partially offsetting. In all regions, the share of lowspeed mil transport will probably continue its strongly (45) decline. We expect that throughout the period 1990～2050, the (46) North American will continue to devote most of his or her 1.1-hour travel-time (47) to automobile travel. The very large demand (48) air travel (or high-speed mil travel) that will be manifest in 2050 (49) to only 12 minutes per person a day; a little time goes a long way in the air. In several developing regions, most travel (50) in 2050 will still be devoted to nonmotorized modes. Buses will persist (51) the primary form of motorized transportation in developing countries for decades. (52) important air travel becomes, buses, automobiles and (53) lowspeed trains will surely go on serving vital functions. (54) of the super-rich already commute and shop in aircraft, but average people will continue to spend most of their travel time on the (55) .
Who can spot the risks The grand circle that regulators have to square is this: how to establish a framework of regulation that accommodates the characteristics of the traditional specialised banking system and mark it off from other businesses. With the sort of diversified financial services that are actually evolving, the era of strictly compartmentalised financial institutions is passing, leaving the regulatory system designed to match it looking increasingly out of date. A single omnipotent, omniscient regulator for all financial services remains dream. Many say it will stay that way, pointing out how long it took to get agreement just on rudimentary international rules for the capital adequacy of banks. Yet regulators everywhere acknowledge the need to cooperate more closely with their opposite numbers across industrial and geographical boundaries. They also agree that greater harmonisation of regulatory standards on everything from reporting requirements to risk assessment will come surely, if slowly. Much of that is likely to be mere tidying up. A good place to start in America would be scrapping the separate regulation of thrifts, If they have been there is little reason not to regulate them as banks (and especially given the mess thrift regulators have made of the job) . It is what Japan has sensibly done by making its equivalent of thrifts, so go banks, choose to be either credit unions or to become commercial banks. Britain, too, has let those of its building societies with ambitions to be banks, and to be regulated as such. These are moves in another right direction to switch away from regulation by institution, as mostly happens now, to regulation by function. This means that regulation becomes a matter of supervising what is done rather than who does it. Unsystematic deregulation has brought the system to its present ugly pass. This has left an increasing number of competitive anomalies. Much of the pressure for, and resistance to, further change comes from those institutions that wish to alleviate or entrench their market disadvantage. In both America and Japan, the debates about reforming the domestic financial systems, and in particular about updating Glass - Steagall and Article 65 respectively, have been slowed by political horse - trading. This is making worse a situation in which competition is keeping the prices of many financial services artificially low and capacity artificially great in a way that cannot be sustained for long. Systemic risk gets greater, not less, the longer the system is skewed. The point is long past at which regulators might have been able to force market practices back into the old regulatory framework. The global competitive and technological forces against them are too powerful. Neither is the option of turning back the clock through re - regulation feasible, and few regulators show signs either of wanting to undertake such a course, or of having the stomach for the political fight it would entail. Even in Japan, where regulators hold a sway over their industries that their counterparts in Europe and America can only envy, and where the financial system is being emerging new economy. This is being done with the grain of market forces, not against it. Which of the following are mentioned in Paragraph 5 as being problems in the present sys- tem
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