Performs arithmetic addition when possible , and concatenates only when both expressions are strings 运算符尽可能执行算术加法运算，只有当两个表达式均为字符串时，才执行连接操作。
I might be able to squeeze a little bit out of concatenating pyrex c strings rather than python string objects , too 我可能需要使用pyrex / c的字符串连接操作，而不是python的字符串对象。
6 hellerstein j m , franklin m j , chandrasekaran s et al . rm adaptive query processing : technology in evolution 针对滑动窗口连接操作的卸载问题，目前开展了许多积极的研究探索并产生了一些研究成果。
Source data of an integration process could come from two or more data sources ; it usually involves different join operations 集成过程的源数据可以来自两个或更多数据源；它通常包含不同的连接操作。
Class is to encapsulate this string , as well as any username password information that might be needed to make a connection 类的主要目的就是封装这个字符串，还有建立连接操作时可能需要的任何用户名密码信息。
Depending upon the number of tables and their respective sizes , a join operation can be very resource intensive and time consuming 连接操作可能要消耗大量的资源和时间，这取决于表的数量以及这些表各自的长度。
First , the definition of view is extended and the peer view , local view and global view are proposed according to the requirements of applications 在pdms中连接操作限制在各个局部pdms中，这样全局物化视图的维护就转化为对各相关局部物化视图的维护。
A join operation on two relations which share a common data item type produces a combined relation with attributes specified in the join operation 对共享一个公共数据项类型的两种关系，连接操作产生一种复合的关系，该关系具有连接操作中规定的属性。
Table functions are powerful because it can make any data source appear like a db2 table , which can be then used in normal sql queries , join operations , grouping , and so on 表函数的功能很强大，因为它可以使任何数据源看起来类似于db2表，然后就可以用于常规的sql查询、连接操作和分组等。
Through interconnected attributes such as keys and foreign keys , this paper investigated the problem of mining association rules across multi - relations without performing join operations 摘要通过关键字等相关属性之间的联系，在不进行连接操作的前提下，探讨任意多表间关联规则的数据挖掘问题。
