数据单位

The optimization methods of database SQL query were studied and some available query optimization Methods were given out as follows: The incompatible data type should avoid to be used; More redundancy search parameters should be given as join condition in join query; In some condition, the number of note hitted to target was estimated by optimizing implement using the average density; Some other maths operating symbol should avoid to be used as condition parameters in WHERE clause; Some operating symbol and its sentence should avoid to be used also; When the cluster function was used,the WHERE clause should be paied attention to more,and so on.

作者单位：（重庆工学院商贸信息学院，重庆 400050）摘要：数据库SQL查询语句的优化，须注意：避免使用不兼容数据类型；连接查询中应多给连接条件提供一些冗余的搜索参数；某种条件下优化器只能使用其平均密度以估计命中的记录数；避免对WHERE子句中条件参数使用其它数学操作符；避免使用某些操作符及相应语句；聚簇函数的使用应注意WHERE子句。

So the convergence rates of space convergence clubs generally are beneath the convergence rates of time convergence clubs.

在同一时间区域组中进行的横截面回归、面板数据分析及单位根检验表明，3个时间区域组内均存在截面型及随机型时间俱乐部趋同，而且，这一结论是相当稳健的。

On this basis, combing characteristics of the agricultural post-graduates job market, stating with the internal and external factors that agricultural graduate students employment faced in the new period , the writer analyzed and summarized the main and direct factors impacting agricultural post-graduate employment trends in Hubei Province which are the employer-oriented factor , employed Agricultural Science Graduates\' judge factor , and post-graduates employment intention factor, and made comparative analysis, cross analysis, correlation analysis and correlation analysis on related data of these three closely research object.

在此基础上，结合农科研究生就业市场自身特点，从新时期农科研究生就业所处的内外部因素入手，分析并概括出影响湖北省农科研究生就业趋势的主要直接因素分别是用人单位取向因素、已就业农科研究生裁判因素和在读研究生就业意向因素，并将这三个互为密切的调研对象的相关数据进行比较分析、交叉分析、关联性分析和相关分析。

A measure of bandwidth or data transfer rate.

一种带宽和数据传输率度量单位。

The maximum data transfer rate permitted, in bytes per second, for anonymous clients.

允许的最大数据传输速率，单位为每秒多少bytes，用于匿名客户端。

The maximum data transfer rate permitted, in bytes per second, for local authenticated users.

允许的最大数据传输速率，单位为每秒钟多少bytes，用于限制本地授权用户。

A set of data that completely defines a unit of work for a computer.

完整地规定了计算机工作单位的一组数据。

A set of related data treated as a unit .

作为一个单位来处理的有关数据的集合。

Data element is a smallest unit of independent marker of information , and the focus work of standardization of information.

数据元是独立标示信息的最小单位，是信息标准化的工作重点。

Acquiring more data in a small unit is only the beginning.

获取更多的数据在一个小单位仅仅是一个开端。

This brought fixed cost, but it also is meant at the same time use a source to won't make you singlehanded assume a problem.

这带来了一定的成本，但它同时也意味着使用开源不会让你独力承担问题。

He gained a small fortune in real estate.

他在房地产上发了一笔小财。