Usually SQL is merely able to sort data by one or more certain fields. When it comes to sorting by a list, the only choice is to use decode or union. But with a long list, the SQL statement will be lengthy. If the items of the list are parameters representing unfixed values, usually a temporary table needs to be create...
2015-09-25 46 0
It is convenient to establish and close a connection to MongoDB in esProc , as well as to call the database to query and count the data, perform distinct and aggregate operations.
1. Preparation for connecting to MongoDB
The MongoDB Java driver (like mongo-java-driver-2.12.2.jar), which esProc does’nt provide, should b...
2015-09-18 38 0
Below is a selection of Collection C1：
You need to group the collection by name. Each group contains the users field of the document corresponding to a same name and does not allow duplicate members. The expected result may like this:
2015-09-16 65 0
In this article, we’ll test the performance of esProc in handling in-memory small data computing, and compare with that of Oracle when performing the same computation.
The test involves two cases: normal simple computing and complicated related computing:
The test data used in normal computing is order information, as ...
2015-09-14 49 0
Parallel computing allows executing a computation on big data by distributing it to nodes. If the data distributed to each node is still in large volume, it can be returned from the node with the remote cursor. We’ll now learn the usage of the remote cursor as well as its features.
1. The usage
The servers the remote c...
2015-09-11 55 0
Two kinds of data file – the normal text file and the binary file – are most used in esProc, of which the binary file adopts compressed encoding of low CPU consumption, meaning that it takes less space than an uncompressed text file, and the data reading efficiency will be higher. Thus, we can conclude that the b...
2015-09-10 47 0
Indexed Sequences in esProc discusses how to create an index of a table sequence or a text file in esProc to greatly speed up the query on desired fields. But how to deal with a data-intensive file whose index table cannot be loaded into the memory? Here let’s look at how to increase the speed of big data handling by c...
2015-09-09 37 0
The SQL implemented by database vendors can be used to write dynamic statements. But since it’s inconvenient to perform set operations and order-related computations in SQL, usually you must resort to the high-level languages to handle the dynamic-column computations, which leads to a cumbersome process of doing these ...
2015-08-31 41 0
In many cases SQL is used to implement a transposition algorithm, such as static/dynamic transposition, natural/inverse transposition, single-/multi-group data transposition, transposition after data alignment/complementing and transposition with/without computed columns. There are different SQL implementations for dif...
2015-08-27 48 0
Not all reporting tools support inter-row calculations directly. When they don’t, you need to write scripts to implement them, which is really a big hassle, even bigger when multilayer data grouping is involved. esProc can deal with this situation thanks to its support for order-related calculations. An esProc script c...
2015-08-24 49 0
You can handle simple file comparisons with the console command, Java, python and perl. But all of them are not good at performing set operations and structured computations. This will result in complicated code for multi-threaded processing and cumbersome process in comparing multiple fields, big files and the files w...
2015-08-20 68 0
Encapsulated lots of functions for handling structured file computing, esProc can import text files with complex formats, carry out cursor-style processing with big files and simplify multithreaded parallel processing. Usually there are three modes in which esProc can be applied: a standalone mode, the execution from c...
2015-08-19 64 0
There are many knotty problems around report development. These include complex layout, which is difficult to build with a reporting tool alone; complex data sources requiring dynamic access and involving different types of databases or non-database data; as well as the handling of order-related computation, subsets of...
2015-08-18 73 0
Java can handle simple parsing of semi-structured JSON data, but has difficulty in handling the in-depth processing. esProc, which supports set operations, order-related operations and dynamic script execution, can help reduce the difficulty. A Java application will execute an esProc script in the same way as it execut...
2015-08-14 188 0
It is difficult to produce unusual report layouts automatically with functionalities provided by reporting tools. But if we can prepare data sources in an appropriate way, the difficulty of building such a report will be significantly reduced.
To do that, we can use esProc (its free edition is available). It not only s...
2015-08-12 39 0