Code reuse can make coding simpler and more efficient for program development. esProc supports basic code reuse by loop, as well as the modular programming in which a subroutine an external cellset is called. Here we’ll explain how to call a subroutine and a cross-cellset program in esProc.
1. Subroutine call
2015-02-02 283 0
During big data computing, besides data traversal and grouping and aggregate operations, sometimes we need to retrieve one group of data each time to analyze. For example, analyze sales data by dates, plot sales curve for each product, and study the purchase habit of each client.
1. Fetch data by groups according to th...
2015-01-30 340 0
esProc has some special ways to produce more orderly and more readable code, among which long statements and computational sub-statements will be illustrated in this article.
1. Long statements
If a long expression cannot be fully displayed when written in a single cell, one can write it in multiple cells according to ...
2015-01-29 393 0
In Excel, groups, as well as summary area and detail area, are independent of each other. There is no inherent operational correlation between cells, so it is difficult to process grouped data. We usually need to write a great many formulas repeatedly, or process every group of data separately, like what is done for so...
2015-01-28 281 0
esProc supports importing big data in batches with the cursor, which is the usual method used in big data computing. Usages of cursors, including external file cursor, database cursor and in-memory record sequence cursor, are basically the same. This article will take the external file cursor as the example to explain ...
2015-01-28 375 0
Functionally, reporting tools like Jasper Report or BIRT can handle the situation where the master report and the subreport(or the table) have their data sources in different databases. But data source names cannot be used directly in the subreport, instead they need to be defined in clear-text database usernames and p...
2015-01-27 401 0
Table sequences are frequently used in esProc. A table sequence can be retrieved from a database, created based on data in a sequence or another table sequence using new function, or derived by using derive function to add a single or multiple columns to an existing record sequence or table sequence.
1.Create a table s...
2015-01-26 245 0
The concept of cursor is very important for the database. With the cursor, data can be manipulated more flexibly and returned from the data table by rows. esProc supports many types of cursor, like database cursor, file cursor and in-memory record sequence cursor, to satisfy various needs in data fetching and processin...
2015-01-23 334 0
Multiple datasources are very common in report development. We would first join tables from different databases before performing subsequent computations, such as filtering, grouping and sorting. With virtual data source or table join, reporting tools like JasperReport and BIRT can in some degree realize these computat...
2015-01-22 418 0
Excel cannot distinguish summary data from detail data due to the lack of inherent operational correlation between cells. Therefore the operation of grouping and filtering data always produces meaningless data. In order to correct the mistake and remedy this defect of Excel, users have to modify the formula for each gr...
2015-01-21 381 0
Reporting tools, such as Jasper Report and BIRT, don’t have enough support for multi-datasources, leading to complicated Java program for realizing dynamic datasources. But by using esProc to assist the reporting tool, this won’t be a problem anymore. The following example will teach you how esProc works to realize the...
2015-01-21 296 0
Sources of data used for analysis usually fall into two categories: the database source and the file source. Compared with the database data, the file data are simple to deploy and publish. The problem is that, since the file data generally need to be used as a whole and thus need to be loaded into the memory all at on...
2015-01-20 273 0
It is difficult to handle operations involving heterogeneous or multiple datasources, such as joins across MongoDB and MySQL, using the reporting tool, like Jasper Report, alone. Indeed Jasper Report and BIRT have the virtual data source or the table join and other functions to deal with them, but the functions are onl...
2015-01-19 243 0
Heterogeneous datasources are frequently needed in report development, but they are difficult to realize using the reporting tool, like JasperReport, alone. To present the result of joining two MongoDB collections together, for instance. Though JasperReport has the functions of virtual data source or table join, but th...
2015-01-16 486 0
esProc provides standard JDBC interface to be easily integrated with reporting tools. This article will explain the integration of esProc and JasperReport respectively in development environment and WEB server-side deployment.
1. Integration in development environment
Access esProc JDBC to call the esProc script using ...