Create a covering index for often-used, high-impact queries.
为最常用和最重要的查询创建覆盖索引。
Covering indexes allow data storage within the index itself while sparse indexes exclude documents that do not contain the missing field.
Covered索引允许在索引本身里存储数据，而Sparse索引则会排除掉不包含索引字段的文档。
The index is a combination of three sub-indices covering wealth, health and education.
该指数由3个次指标组成，涵盖了财富，健康和教育领域。
The answer to the question as stated in your subject line in general is no. Because you generally would much prefer to have the narrowest covering (probably non-clustered) index.
这个问题的答案所你的主题一般是否定的。因为你通常可能更倾向于有窄覆盖(可能非集群)指数。
The price-earnings ratio of the index, covering both the Shanghai and Shenzhen Exchanges, has dropped from the highest point of 53 times to the current 14.36 times, the lowest point since 1995.
沪深300的市盈率已由最高点的53倍跌至目前的14.36倍，为1995年以来的最低水准。
Through the new system, the search engine can implement larger scale Web covering and faster index updating, and provides better searching service.
通过这个新的系统，搜索引擎能够实现更大规模的网页覆盖和更快的索引更新，从而提高更好的搜索服务。
The Engineering Index Annual is an organized compilation of bibliographic citations and abstracts covering the world's technological literature in all engineering disciplines.
《工程索引》年刊是以条目摘要形式编辑而成的技术文献检索工具。 其内容覆盖世界范围内所有工程领域。
Because you generally would much prefer to have the narrowest covering (probably non-clustered) index.
因为你通常可能更倾向于有窄覆盖(可能非集群)指数。
Although easily available and searchable on-line, the CFR 21 is a vast document covering a wide range of subjects but contains no index.
虽然容易得到，网上搜索，病死率21是一个巨大的文件，涵盖的学科范围广泛，但不包含索引。
John sailed forward-covering the distance in two strides, his left arm a blur shooting forward, index and middle fingers outstretched together to form a spike.
约翰冲向前方——两步跨完了剩下的距离，左壁子弹般向前，食指和中指伸出并拢形成尖峰状。
The results showed that each performance index of the product was better than that of ordinary wall covering.
结果表明，该产品各项性能指标值优于普通墙布水平。
The covering material that encases the core of an optical fiber. the cladding material usually has a lower index of refraction than the core material and may be either glass or plastic.
一种包装光纤芯的保护材料。保护材料的折射率通常比光纤芯的折射率低，它一般是玻璃或塑料。
Index of online resources covering topics including human and physical geography, cartography, planning and transportation, and remote sensing.
在线资源标引着主题，包括人类与地理，绘图法，规划与交通，及遥控探头。
A subject based article index is offered, covering topics such as biodiversity, climate, nuclear energy, sustainability, and transport.
还有以题目分类的文章，包括生物差异性，核能，可持续性等。
A subject based article index is offered, covering topics such as biodiversity, climate, nuclear energy, sustainability, and transport.
还有以题目分类的文章，包括生物差异性，核能，可持续性等。
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