Problem source: http://bbs.csdn.net/topics/330190185 .
There are multiple text files in a certain directory. Each of their names includes one of the letters a/b/c at the beginning and a date. The letter is fixed while the date is dynamic. You need to write contents of these files as well as the dates into a ...
2015-05-15 959 0
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Regarding the chart element plotting, compared with setting the appearance properties for a chart element like color and line style, it is more important to specify its position. When plotting a chart, statistical values are often used to determine its position. Therefore you will need to create a coordinate system on ...
2015-05-14 1151 0
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During processing the text file, sometimes we need to remove duplicate rows from the grouped data. But the operation becomes complicated when the file under processing is too big to be entirely loaded into the memory. esProc’s group operation supports importing a whole group of data with the file cursor, as well as man...
2015-05-14 995 0
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In databases, creating appropriate indexes for tables can greatly increase query efficiency. Similarly, index sequences can be created for record sequences or table sequences in esProc to increase efficiency in querying data repeatedly.
For example, we need to access the food order Order_Foods.txt repeatedly.
...
2015-05-13 977 0
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Many databases support the MERGE statement and thus can merge two tables conveniently. Database syntax cannot be used directly, however, if the data to be merged are the text data. In this case esProc is able to perform what MERGE statements can do based on the text files.
The two files – table1.txt ...
2015-05-13 797 0
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With esProc, you can handle the structured big data easily, and perform data computing and analysis without difficulty. Because the big data table cannot be loaded into the memory all at once, the basic solution is using cursor to handle it.
1. Basic principle of cursor
The esProc cursor is like the database cursor in ...
2015-05-12 862 0
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The article esProc File Computing: Parallel Query and Filter explained how to query and filter data. Here let’s look at the case of combining the article’s topic with grouping and aggregation. Still we only discuss cases with relatively small result sets that can be loaded into memory in one go.
Steps of queryin...
2015-05-12 793 0
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1. Foreign key referencing
The foreign key is a common concept for various relational databases. In a relational table, you can define one or multiple fields as the foreign key. The foreign key field values can be associated with the data in another table. For example, in the game scoring report, player scores are usua...
2015-05-11 1008 0
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esProc supports cursor objects and provides related functions to process big text files conveniently. Below is an example.
Suppose a text file, sales.txt, stores ten million sales records. Its fields mainly include SellerID, OrderDate and Amount. Requirement: Computing each seller’s total amount of big orders in the pa...
2015-05-11 40840 0
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Problem source：http://stackoverflow.com/questions/28976554/removing-duplicates-from-csv-and-rearranging-the-data-into-columns-with-java .
JAVA doesn’t have the class library for grouping data from a text file or getting distinct values, which results rather complicated coding. In dealing with the duplicated ...
2015-05-07 903 0
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1. Sequences and sets in esProc
Unlike traditional programming languages, esProc employs sets commonly. In fact, the sequence in esProc belongs to the field of set. So it’s quite important to deeply understand the concept of sets when using esProc. Like an integer and a string, the set is a basic esProc data type; it c...
2015-05-07 849 0
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Raqsoft esProc provides the ability of performing file-based computation. It supports multithreaded parallel processing to deal with problems involving relatively big data. The multiprocessing can make full use of the computational power of the machine’s multi-core CPU to achieve an almost equal or better performance t...
2015-04-30 1016 0
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There are some computational tasks of processing structured data that involves multi-table data sources joined through cascaded foreign key relationships. For example, you want to find particular orders from the order management system, where the following structure of cascaded foreign key relationships is involved. Co...
2015-04-29 824 0
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In data analysis, we often need to group data and then compute the aggregate value for each group, or perform other computations on each group. esProc allows using groups function to compute aggregate values for groups of data, as well as grouping records of a table with group function for use in subsequent computation...
2015-04-28 907 0
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esProc provides standard JDBC to integrate with BIRT and other reporting tools. Here we’ll explain the process of integration of esProc and BIRT in development environment and WEB application environment.
1. Integration in development environment
1.1 Create configuration files
Create the two configuration files –...
2015-04-27 2180 0
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