Quite a few unconventional statistical computations are difficult to handle with the reporting tools, like Jasper or BIRT, alone or in SQL. For example, to achieve an effect in a report similar to that of the group_concat function based on MS SQL/Oracle.
Having a powerful, integration-friendly computational engine for ...
2015-01-14 132 0
Excel is the favorite of business staff because of its simplicity and easy use, but actually many of the common operations are not so easy to perform with it. The computations of link relative ratio and year-on-year comparison fall into this category. This is because, during the copying of formulas, Excel can only comp...
2015-01-13 118 0
It is common to sort records in the table during data analysis and computing. In esProc, sort function is used to sort data in the sequence or the table sequence. External memory sorting is required when data being sorted are massive and cannot be loaded into memory all together, for the ordinary sorting method cannot ...
2015-01-13 145 0
Besides being used to query data in a database, SQL is also used to update them. In esProc, you can use the SQL commands directly to return a query result, or use update function to modify a database with the data from a table sequence or a sequence.
1. Update a database with SQL commands
In esProc, db.execute(sql) fun...
2015-01-12 116 0
The strings in esProc sometimes include some special identifiers that may cause ambiguity about the expression. So does the names of fields in a table sequence sometimes. The following will teach you how to deal with them properly.
1. Special identifiers in strings
A string may include various signs, some of which coul...
2015-01-09 141 0
Users often need to perform set operations in Excel, which, however, doesn’t directly support data of set types and thus cannot deal with set operations like intersection and union. The operations can only be realized using lookup functions like VLOOKUP or through special techniques, with great difficulty though.
2015-01-08 132 0
In relational databases, a foreign key is often used to identify the relationship between tables. In esProc, this relationship of correspondence can be expressed by the foreign key field.
1. Computed columns and foreign key fields
T.derive() function is used in esProc to add computed columns to a table sequence, for ex...
2015-01-08 178 0
A sequence is an ordered set consisting of some data, which are called members of the sequence. A sequence is similar to an array in high-level languages, but the data types of its members not necessarily the same. The following will explain its basic computation through creation, access, operators and functions.
2015-01-07 105 0
During our dealing with the database transactions, some operations may produce errors which could bring unexpected results, particularly during batch processes. In order to prevent this from happening, we need to manage the data connection in a right way and handle those errors properly.
1. Database error messages
2015-01-06 141 0
After data are imported from a data table, we often need to group them as required, or work out grouping and summarizing result. In esProc, groups function is used to compute the result of data grouping and summarizing; or group function can be used to first group the data, then perform further analysis and computation...
2015-01-06 166 0
In esProc, the storage of cellset variables is ubiquitous. Cell values are convenient references during computation, but they could occupy too much memory. Data can be cleared from cells to reduce memory footprint after they accomplish their mission in computation. It should be particularly noted that, when the interme...
2015-01-05 162 0
The usual way to insert summary values into the grouped data is to process data group by group. Import a group of data, append them and their summary value to a new file and then do the same with the next group, and so on. But it is not easy to realize this in hard coding. esProc, however, supports group cursor with wh...
2015-01-05 158 0
Table sequences are universally used in esProc. During data analysis and computing, we often need to add records to a table sequence or delete them from it, or modify the data in it. This article will illustrate the modification and maintenance of the table sequences through operations of adding, deleting and modifying...
2015-01-04 119 0
When parsing logs into structured data, we often find that the records consist of a variable number of lines. This makes the conversion, as well as the corresponding operation, quite complicated. Equipped with various flexible functions for structured data processing, such as regular expressions, string splitting, fetc...
2014-12-31 142 0
In esProc, we can use not only the SQL to retrieve data from databases, but also the preliminary database query results to perform further analyses and operations to solve some complicated problems which are difficult to deal with in SQL alone.
1. Database connection and disconnection
When SQL accesses databases, it sh...
2014-12-30 164 0