Sometimes you need to reference data sources dynamically through a parameter, merge data sources into one, or dynamically pass data source name to a subreport/Table control. Often reporting tools – especially those with support for single data source, such as BIRT and Jasper – have to use a high-level language to...
2015-06-18 793 0
Java provides functions for handling the basic file processing, which refers to the retrieval of small text files, in a simple, unstructured way. But in handling files requiring structured format, holding data of various formats and having particular requirements, or big files that cannot be entirely loaded into memory...
2015-06-17 222 0
It’s hard to create reports with unconventional layouts directly with functions provided by a reporting tool. However, if the data for building such a report can be beautifully prepared, the difficulty could be considerably reduced.
esProc(free edition is available) is an expert at handling this data preparation. It pr...
2015-06-15 210 0
Sometimes you need to query a big text file, instead of the database. In those cases, you need to retrieve the file in a stream style to perform the query algorithm, in which parallel processing is needed to improve the computing performance. As Java lacks the class library for doing these, you have to use hardcoding t...
2015-06-12 155 0
This article aims to test esProc performance of retrieving files and compares it with the result got by using Oracle JDBC.
The test data is some order records saved in the orders.b file. Import the file with esProc and its content would be like this:
ORDERID CLIENT SELLERID AMOUNT ORDERDATE NOTE...
2015-06-11 160 0
This article aims to test esProc performance in processing files concurrently, based on filter, group and aggregate operations and comparison with Oracle.
Test data includes tables of ordering information of different years. With esProc, files (Orders2009.b, Orders2010.b, Orders2011.b and Orders2012.b) of binary format...
2015-06-10 172 0
It is not uncommon in actual business to tackle complex computational problems by composing dynamic SQL. The skill has generated a lot of discussion across online IT forums. Here are links to some of the questions around it:
2015-06-09 155 0
This article focuses on testing performance of esProc’s handling of file traversal, using commonly used group and aggregate operations as well as query and filter operations. The performance test will include evaluation of the influence of using multithreads, and comparison between esProc approach and Oracle counterpar...
2015-06-05 175 0
In some cases, data must be stored in the file system, rather than in a database. That requires handling file-based data computing manually. Since Java lacks the related class library, you have to hardcode the structured file computing, which produces complicated and unreadable code.
Yet, you can make up for this defic...
2015-06-04 317 0
24-point game is a common intellectual game, which can be played with cards without jokers. The rule is to draw four random cards and manipulate the four numbers to get the result 24 using four arithmetic operations: addition, subtraction, multiplication and division. In card playing, J, Q, K correspond numbers 11, 12 ...
2015-06-03 148 0
For a given system of linear equations in n unknowns, there must be n equations to form the system. e.g.:
Well, how do you solve this system of linear equations with n variables with esProc? First, the system of equations should be written in a standard form, and parameters are fill...
2015-06-02 204 0
Among lots of chess puzzles, the problem of the eight queens is the most well-known example. Eight queens must be placed on a 8×8 chessboard so that no queen attacks any others. Well, how many solutions are there?
A queen attacks any other queen that sits on the same row, column or diagonal. Thus a solution requi...
2015-05-29 148 0
A link-relative ratio is a percentage got by comparing the data of current period and that of the previous period. Usually the interval between the two periods is a month (sometimes an hour, a day, a week and a quarter). The link-relative ratio of April is computed by dividing, for example, its sales amount by that of ...
2015-05-28 161 0
If k (a single field or a combination of fields) is table M’s primary key, and k, at the same time, exists in table B, then k is regarded as B’s foreign key. The foreign key defines a relationship between two tables and is one of the most important concepts for structured data computing. Through object references, esPr...
2015-05-27 165 0
It’s difficult to handle unconventional statistical tasks using simply the reporting tool, like Jasper or BIRT, or SQL. One of the cases is that the source data don’t meet the crosstab’s requirements and thus need to be transposed for display. Having powerful computing engine to process structured data and being integr...
2015-02-09 202 0