selectivity中文，selectivity的意思，selectivity翻译及用法

selectivity 英语释义

英语释义

the property of being selective

selectivity 片语

片语

biochemical selectivity生化选择性

mode selectivity模选择性

selectivity coefficient[土壤][分化] 选择系数

solvent selectivity溶剂选择性

separability[数] 可分性，分离性

polarization selectivity偏振选择性

perceptual selectivity选择性

catalyst selectivity[物化] 催化剂选择性

selectivity index选择性指数

motivated selectivity动机性选择

selectivity 例句

英汉例句

sometimes, due to a skew in the distribution of data, the nature of the predicate or the query, or insufficient statistics, the optimizer「s selectivity estimates may not be accurate.
有时候，由于在数据分布上的一点偏差，加上谓词或查询的特性，或者由于统计信息不充分，可能导致优化器的选择性估计不準确。
given accurate statistics, the query optimizer generally comes up with correct selectivity estimates.
如果有了準确的统计信息，那么查询优化器一般能够得出正确的选择性估计。
thus, different functional molecules can be immobilized to the different components of the hetero-nanostructure to enhance selectivity and specificity of detection.
因此，不同的功能分子可以被固定于不同的异质性纳米结构组分上，以此来加强检测的选择性与特异性。
in particular, it is rather hard for the optimizer to determine the costs and the selectivity of such an index scan.
而且，优化器很难判断那样的索引扫描的成本和选择性。
for simple cost calculations, we suppose an idealized number of rows in each table and assume that the selectivity of the filter on each dimension table is 1/10 for the following query.
对于简单的成本计算，我们假设每个表中都有足够的行数，对于以下查询，每个维度表的过滤选择度为 1/10。
mustapha」s modification lets food scientists use the pcr test to capitalize on its speed, selectivity and sensitivity, but avoid false-positive tests by differentiating between dead and live cells.
幕斯塔法的修改使食品科学家在使用pcr测试时，可以有效利用其高效性、有选择性和敏感性，并且通过区分死亡细胞和活细胞避免误测。
for the exceptional situations where the optimizer cannot choose an optimal query execution plan, db2 has added features such as the selectivity clause and optimization guidelines.
对于优化器不能选择最佳查询执行计划的例外情况，db2已经增加了诸如selectivity子句和优化指南之类的特性。
in other words, the optimizer overestimated the selectivity of the local predicates on the table.
换句话说，优化器过高估计了本地谓词对表格的选择性。
this suggests a much better predicate selectivity than it appears to be!
这表明谓词选择性比其表现出来的还要好！
the approach chosen be the db2 development team to close this gap immediately resulted in giving the user the ability to provide an estimate for the selectivity of a spatial predicate.
db2开发小组目前选择的解决方案使用户可以提供对空间谓词选择性的估计。
for comparison, figure 3 illustrates the access plan where i forced the db2 optimizer to ignore the index by adding the clause selectivity 1 to the predicate in the where clause.
为了便于比较，图3显示了通过将selectivity1 子句添加到where 子句的谓词中，强迫db2优化器忽略索引的访问计划。
selectivity is key to its success.
选择性是成功关键。
however, in the absence of data distribution information, the optimizer will calculate selectivity for filters of different types based on table indexes.
然而在缺乏数据分布信息的情况下，优化器将基于表索引计算不同类型筛选器的选择性。
to that end, you can append the selectivity keyword right after the predicate in the where clause, followed by an estimated or guessed selectivity value in the range of 0 and 1.
为此，可以在where子句中将关键字selectivity 放在谓词的后面，后面带一个0到1 之间的对选择性的估计值。
and all ion channels are selective for a single type of ion, and we can think about how that selectivity takes place, and that「s where this idea of atomic radius is going to become very important.
所有的离子通道都是仅对某一种离子具有选择性的，而我们可以来想一想这种选择性是如何发生的，这也就是原子半径这个概念将会变得，非常重要的地方。
now that you」ve analyzed the selectivity of the local predicates, let's now look at the table selectivity.
已经分析了本地谓词的选择性，我们再看看表的选择性。
so it is obvious that the accuracy of selectivity estimation depends upon how often you run update statistics.
因此，选择性估算的準确性显然基于您运行updatestatistics 的频率。
but the selectivity calculated in this way is not as accurate as selectivity calculated using data distribution.
但是，使用该方式计算的选择性不如使用数据分布计算的选择性準确。
missing statistics can cause the optimizer to overestimate or to underestimate the selectivity of a predicate, and eventually to select an inefficient access path.
丢失的统计数据会让优化器高估或低估谓词的选择性，最终会选择低效的访问路径。
for example, if the indexed column has literal values and null values, then the selectivity is equal to the number of distinct keys in the index.
例如，如果索引列包含字面值和null值，那么其选择性就等于索引中不同的键的数目。
the optimizer uses data distribution information generated by update statistics to calculate selectivity for the filters in the query.
优化器使用updatestatistics所生成的数据分布信息来计算查询中筛选器的选择性。
this information can then be included as part of the optimizer decision during costing for selectivity and cardinality estimates for qualified queries which do not need to reference the view directly.
然后，这些信息被包括进来，用于帮助优化器在为那些符合条件的查询（这些查询不需要直接引用视图）的选择性估计和基数估计计算成本时做决定。

selectivity 同义词

相似词

option[计] 选项；选择权；买卖的特权

selectivity 反义词

相反词

nonselective无选择的

unselective不加以选择的