MongoDB doesn’t support join. The unity JDBC recommended by its official website can perform join operation after retrieving data out, but charges a fee for the service. Other free JDBC drivers can only support the basic SQL statements, without join included. If you use programming languages, like Java, to retrieve dat...
2014-12-11 173 0
While importing the structured text files into the database using Java alone, we need to combine the SQL statements together manually, and to deal with various troublesome situations as well, like if the data in a table has been existed, whether we should update it or insert data into it, if some fields are included in...
2014-12-10 142 0
An Excel sheet hasn’t sequence numbers to mark the relative positions of the data, so it is very inconvenient to filter detail data of each group automatically. Usually one can only handle the data manually and this requires a lot of work. With esCalc, however, one can handle them easily. Here is an example:
2014-12-10 120 0
There are many occasions during text processing which require performing string matching with big files. Coding with command line grep\cat is simple yet inefficient. Though higher efficiency can be achieved with high-level languages, coding will be rather difficult.
Yet this operation, as well as multithreaded parallel...
2014-12-09 125 0
Multi-level relationships are one of the complicated SQL-style computations which we often need to deal with during database application development. The relatively abstract SQL JOIN statement is suitable for expressing simple relationships between tables, but once the multi-level relationships are involved, the code b...
2014-12-09 86 0
During text processing, you often have the tasks of querying data from a big file on one or more conditions. Command line grep\cat command can be used to handle some simple situations with simple command yet low efficiency. Or high-level languages can be used to get a much higher efficiency with complicated code. If th...
2014-12-08 261 0
It is common to perform set operations on big files in text processing. For example, find different rows between two files. The code for handling the operations with command line grep or cat command is simple but inefficient. While the operational efficiency is high when high-level languages are used to handle the oper...
2014-12-05 137 0
It is a common task to group records in a table sequence as needed and to summarize the data in each group during data analysis and statistics. This includes data summarizing like summing up and averaging, as well as the listing of the top n records, and etc. This article will explore how to group and summarize the dat...
2014-12-04 353 0
During database application development, we are often faced with complicated SQL-style computations, to which the multi-layered data grouping with specified criteria belong. In SQL, the key method for realizing the operation is to group the source data according to specified criteria using left join statement. The prob...
2014-12-03 134 0
It is extremely difficult to sort summary values in Excel, as the groups in an Excel spreadsheet are isolated from each other. In Excel, users can select a batch of data and sort them, but they cannot sort data that are scattered over different groups. A great deal of manual work is needed to fully realize the operatio...
2014-12-03 121 0
MongoDB can find out elements of a built-in array according to their indexes, but cannot find the indexes through the values of the elements. For example, the elements of an array are names of people stored according to their rankings. In MongoDB, names can be found according to the rankings (indexes of the array), but...
2014-12-02 113 0
MongoDB uses unicode, instead of the coding for a certain local language, to sort data in this language (i.e. Chinese). Together with esProc, MongoDB can realize sorting in local language conveniently (i.e. sort Chinese according to Chinese phonetic alphabet). The following will teach you the method in detail by taking...
2014-12-01 156 0
Java doesn’t support set operations directly, so nested loops have to be used to realize the operations of intersection, union, complement and etc. between text files. If there are many text files, or the file to be computed is too big to be loaded into the memory, or it is required to perform set operations according ...
2014-11-28 144 0
Inter-row computation is one of those complicated SQL-style computations we often need to handle during database application development. For instance, to compute the link relative ratio by dividing each month’s sales amount by that of the last month, or to compute the year-on-year comparison by dividing each month’s s...
2014-11-27 125 0
esProc supports a variety of heterogeneous datasources, including the databases. This article will introduce the methods of esProc’s connection to various databases.
1. Configure datasource manager
To connect to a relational database, please follow these steps:
1) Click Datasource connection on Tool options menu to ope...
2014-11-26 223 0