who have efficient ways for data process in java?

In Java development, the typical data computation problems are characterized with:

•Long computation procedure requiring a great deal of debugging
•Data may from database, or Excel/Txt
•Data may from multiple databases, instead of just one.
•Some computation goals are complex, such as relative position computation, and set-related computation

a sales department needs to make statistics on the top 3 outstanding salesmen ranking by their monthly sales in every month from Jan to the previous month, based on the order data.

As aggregating, filtering, grouping, sorting, and ranking are involved, programmers have to use List and other objects to assemble every 2D table and every piece of data, and then arrange the nested multi-level loops. In addition, such computation involves set and relation operations on massive data, or relative position between object and object properties.

I dont know how java can solve this issue, but I think SQL will be one of options.

First, SQL takes a long query as a basic computation unit. Programmers are only allowed to view the final result but not the details of running. It is awkward to prepare the stored procedure and a great many of stage tables just to debug barely. Using special scripting for debugging? Low cost-efficiency indeed! A lengthy SQL statement will bring about exponential increase in the difficulty of reading or writing, possibility of error, and maintenance cost.

Second, to address the Excel, text, or heterogeneous data computation with SQL, programmers have to establish the data mart or global view with ETL or Linked Server at great cost. In addition, SQL does not support the step-by-step computations for decomposing the complex computation goal. Its incomplete support for the set makes programmers still feel tough to solve some complex problems.

So, we can conclude that SQL has limited impact on improving the computational efficiency for Java.

In this case, esProc is highly recommended – a database computation development tool ideal for simplifying the complex computations and tailored for cross-database computation and explicit sets with convenient debugging, and direct support for JDBC to integrate with the Java apps easily.Still the above example, esProc scripts are as shown below:

A B
1 $select * from salesOrder
2 =date(string(year(now()))+”-01-01”) =pdate@m(now())
3 =A1.select(salesDate>=A2 && salesDate<B2
4 =A3.group(name,month(salesDate);name,month(salesDate):month,
~.sum(sales):monthSales)
5 =A4.group(month)
6 =A5.(~.dup@t().derive(~{}.(monthSales).ranki(monthSales):r))
7 =A6.(~.select(r<=3))
8 =A7.(~(name)).isect()

esProc boasts the grid-style and agile syntax specially designed for the massive amount of structured data. In addition, esProc can directly retrieve and operate on the data from multiple databases, Text files, and Excel sheets. With the support for external parameters, native support for cross-database computations, and code reuse, esProc boosts the data computing efficiency of Java greatly.