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MongoDB can find out elements of a built-in array according to their indexes, but cannot find the indexes through the values of the elements. For example, the elements of an array are names of people stored according to their rankings. In MongoDB, names can be found according to the rankings (indexes of the array), but the values of rankings cannot be determined through names. esProc can help MongoDB in realizing this operation. The following example will teach you how it works in…Continue
Added by Lynn Guo on November 19, 2014 at 6:30pm — No Comments
Cross-row and group computation often involves computing link relative ratio and year-on-year comparison. Link relative ratio refers to comparison between the current data and data of the previous period. Generally, it takes month as the time interval. For example, compare the sales amount of April with that of March, and the growth rate we get is the link relative ratio of April. Hour, day, week and quarter can also be used as the time…Continue
Added by Jessica May on September 22, 2014 at 2:00am — No Comments
The computing power of SQL for mass structured data is complete, that is to say, it is impossible to find anything that SQL cannot compute. But its support layer is too low, which can lead to over-elaborate operation in practical application.…Continue
Added by Jessica May on July 27, 2014 at 9:30pm — No Comments
OLAP is an important constituent part of BI(business intelligence).
Understood literally, OLAP is online analytical processing, that is, users conduct analytical operation on real-time business data.
But, currently the concept of OLAP is seriously narrowed, and only it refers to operations such as conducting drilling,…Continue
Added by Jessica May on May 27, 2014 at 8:00pm — No Comments