July 29, 2015

esProc Assists Jasper in Calculating Opening Balance

Problem source:

The calculation of opening balances according to deposit and withdraw amount involves inter-row operation. Jasper can do the calculation but the code is complicated. You can use esProc to assist the job and make it easy. The following is a simple example.

data.csv contains deposit and withdraw information of different sum of money in an account. You need to calculate the opening balance based on this file. Below is a selection from the original data:

esProc code:

A1: Import the file separated by commas.

A2: Calculate opening balance and return result to the report. The initial value of the account is 43. Operations using parentheses will return result of the expression after the last comma. A2’s result is as follows:

esProc provides JDBC interface. Reporting tools will identify it as a normal database.

Now you can create a simple list table with Jasper in the following template:

Below is a preview of the finished report:

A report calls an esProc script in the same way as it calls the stored procedure. Save the above script as balance.dfx. You can invoke it with call balance() and input parameters into it from Jasper’s SQL designer.

July 28, 2015

esProc Assists BIRT in Handling Irregular Month Grouping

Problem source:
 
Irregular month grouping: If the start date is 2014-01-10, group dates from this date to 2014-02-09 together and dates from 2014-02-10 to 2014-03-9 together. If the start date is 2014-01-31, put dates from this date to 2014-02-27 into a group and take dates from 2014-02-28 to 2014-03-30 as a group.

esPro code:

A1: Query database according to the start date and end date. Both startDate and endDate are external parameters.

A2: Count the number of months between the start date and the end date. For example, there are 6 month between 2014-01-31 and 2014-07-31.

B2: Find the day when each of the irregular months begins according to the initial start date and the intervals. Put the start date before the expression for this computation. The sign “|” represents concatenation and “~” represents the current member in the set, i.e. the numbers from 1 to 6. after function is used to get the irregular months.

A3: Group A1’s data by B2’s intervals and calculate sales amount for each of these irregular months; B2 is appended as the last column. pseg function returns the sequence number of the interval in which the data is held. “~” in ~.sum(Amount)represents the current group. “#” represents the sequence number of the current group. Result is as follows:

A4: Retrieve the second and third column from A3 and return them to the reporting tool. esProc provides JDBC interface outward to be identified by a reporting tool as a normal database.

Create a simple list table with BIRT:

esProc script in the same way as it calls the stored procedure. Save the above script as BirtUnregulMonth.dfx. You can invoke it with call BirtUnregulMonth(?,?) from BIRT’s stored procedure designer. Below is a preview of the appearance and layout of the result report:

July 27, 2015

esProc Assists BIRT in Splitting Fields and Converting Them to Records


To split fields apart and recombine them into records, you can use the stored procedure or a report script. But as the code is complex, an alternative choice is using esProc to help the reporting tool with the job. Let’s look at an example.

Database table data has two fields: ID and ANOMALIES. You need to split ANOMALIES field into strings by the space and combine each string with the corresponding original ID value to generate new records. Below is the original data:

esProc code:

A1: Query the database.

A2: Split ANOMALIES field to create a new two-dimensional table. Then use conj function to concatenate the records generated from the processing of each of A1’s members. “~” represents the set member under processing. A2’s result is like this:

A3: Return A2’s result to the reporting tool. esProc provides JDBC interface outward to be identified by a reporting tool as a normal database.

Create a simple list table with BIRT:

A preview would be like this:
The way a report calls an esProc script is the same as that it calls the stored procedure. Save the above script asBIRTsplitrow.dfx. You can invoke it with call BIRTsplitrow() and input parameters into it from BIRT stored procedure designer. 

July 24, 2015

esProc Assists BIRT in Handling Intragroup Inter-row Calculations

Problem source:

Generally intragroup inter-row calculations are handled with window functions or report scripts. But the code is rather complicated. Instead, you can use esProc to assist reporting tools in dealing with them. Below is such an example.


Database table sample has three fields, among which id is the grouping field. You need to design a grouped table where id is the grouping field and the other fields holding detail data include v1, v2 and the computed field crossline. 

crossline will be calculated like this: v1+v2+previous v1+previous v2. Below is the original data:

esProc code for data preparation:

A1: Query the database and create an additional field with constant values for later use.

A2: Group A1 by id, modify crossline values for each group and combine groups of data together. Result is as follows:
A3: Return A2’s result to the reporting tool. esProc provides JDBC interface outward to be identified by a reporting tool as a normal database.

July 23, 2015

esProcImplementsDynamic Data Sources for Reporting Tools

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 accomplish these requirements, or trade security for reduced complexity.

However, they can work with esProc (free edition is available) to offset their disadvantages. esProc encapsulates a large number of functions for handling structured data, supports parsing expression dynamically and handling computations involving multiple data sources, and creates dynamic data sources with simple scripts. In addition, it provides simple and easy-to-use JDBC interface through which a reporting tool gets the result of executing esProc script, which will be recognized as a database stored procedure and receive parameters from the reporting tool.


Below is structure of integration of an esProc script and a reporting tool:

Now, through an example, let’s look at the basic process of esProc’s switching data sources using the parameter:

myDB1 and oraDB are data sources that point to different databases. Each holds a sOrder table with the same structure. The report requires connecting to data sources dynamically via a parameter, querying sOrder for orders whose amounts are greater than 1,000, and displaying them.

Below is a selection from the sOrder table in myDB1:

Here is a selection from the sOrder table in oraDB:

esProc script:
=${pSource}.query("select * from sOrder where Amount>?",pAmount)

Both pSource and pAmount are report parameters. pSource represents the data source name; ${…} indicates parsing a string or a string variable into an expression. pAmount stands for the order amount.

When pSource=“myDB1”, A1 has the following result:

When pSource=“oraDB”, A1 gets this result:

The reporting tool calls the esProc script via JDBC, in a same manner as it calls the stored procedure from a normal database. The syntax is this: call esProc script name (para1…paraN). The result returned from the script participates in report creation in the form of a normal data set. Details are covered in the following documents:esProc Integration & Application: Integration with JasperReport and esProc Integration & Application: Integration with BIRT.

As a professional tool for handling data sources for reporting tools, esProchas more abilities, which you’ll see in the following cases. 

Perform a multi-data-source pre-join

The mySQL database stores a Sales table holding orders from different sellers per day. Its SellerID field contains seller numbers. In MSSQL database there is an emp table of seller information in which EID field contains seller numbers. Create a report to display order numbers, order dates, order amounts, seller names and their departments, based on the condition that the orders should be within the last N days (say 30 days) or belong to certain important departments (say Marketing and Finance). Below are selections of the original tables:

Database table sales

Database table emp

esProc script:

A1,A2:Database queries. myDB1 and myDB2 point to MySQL and MSSQL respectively.

A3: Replace A1’s SellerID field with the corresponding records in A2 according to the key field EID. The result is as follows (the data items in blue contain sub-members):

By default, when there is not a corresponding record in A2 for a SellerID value, switch function retains the A1’s record while the SellerID shows an empty value. The effect is like a left join. Use @i option if you want to perform an inner join. The code is A1.switch@i(SellerId,A2:EId).

A4: Filter on the result of join. The first filtering criterion is that orders are within the last N days (this corresponds to parameter days),whose expression isOrderDate>=after(date(now()),days*-1). The second one is that orders belong to several important departments (this corresponds to parameter depts), whose expression is depts.array().pos(SellerId.Dept). The operator || denotes the logical OR operation.

after function calculates the relative time duration. array function splits a string into a set using delimiters. posfunction locates a member in a set. SellerId.Dept means Dept field in the record corresponding to SellerID field.

Both days and deptsare parameters transferred from the reporting tool. Suppose their values are respectively 30 and “Marketing,Finance”, then A4’s result is as follows:

A5: Get the fields of interest from A4. Here is the final result:

Combine result sets with union

Result sets ds1 and ds2 have the same structure, but they come from different data sources – MySQL and a text file respectively. Now concatenate them and display the result in a cross table. Below is the original data:

esProc script:

A3: Concatenate the two data sets. The reporting tool’s work is just to create a simple cross table based on the resulting one data set. 

Handle different data sources for main report and subreport

For a reporting tool that can support only one data source, if the reporting requires different data sources for the main report and the subreport, it needs to pass in the database URL explicitly or use Java classes to combine the different data sources into one. The former approach is vulnerable to security problems and the latter one produces complicated code. esProc, however, is able to cope easily. Here is an example.

Build a report with a subreport to display order information of sellers whose salaries are within a certain range. The main report’s data source is an emp table (in MySQL database) and the subreport’s data comes from a sales table (MSSQL database).

esProc scripts:
empEsProc.dfxfor the main report

A1: Query the emp table in MySQL database by the salary range.

salesEsProc.dfxfor the subreport

A1: Rrtrieve orders records from the sales table in MSSQL database according to employee IDs. Suppose eid=1, the result would be:

You can see that the two data sources have been joined into one source with esProc. The reporting tool just needs to call the corresponding esProc script for the main report and the subreport.

Some reporting systems do support multiple data sources. But it is hard to handle reports with different and changeable data sources. In that case, using esProc to generate a single data source can make the handling work easier.

For the same reason, another reporting problem can be solved through esProc’s single-data-source solution. That is the “multiple subreports, multiple data sources” problem, which means there are many subreports (or table controls) within one report and each has its own data source.

Perform dynamic join between main report and its subreports

A main report may use many subreports whose data sources come from multiple databases. The reporting needs to display the result of dynamic join between these data sources and the one the main report uses. esProc implements the task in a simple way. For example:

The main table org is stored in the data source Master. Every record of the org table corresponds a subtable that has a separate data source. For example when org.org_id=“ORG_S”, the record’s subtable is the User able in the data source S_odaURL; when org.org_id=“ORG_T”, the record’s subtable is the User able in the data source T_odaURL. There are more subtables with names all being User. You need to join all subtables dynamically with the main table and display the result data setin a report. Below is the logical relationship between these tables:

esProc script:

A1:Execute the SQL statement to retrieve data from the org table in Master data source. arg1 is a parameter passed from the reporting tool. When arg1=”ORG”, the result would be:

A2:Loop through A1’s records to associate one subtable each time,concatenatingeach result of join into B2. esProc uses the natural indentation to represent the loop statement’s working range. Here the loop body is B2-B7 where A2 is used to reference a loop variable and #A2 is used to reference the loop number.

B2: Get the data source name for each record according to its org_id field. The result during the first loop is “S_odaURL”.

B3: This is the explicit connectionto corresponding data source.

B4: Filter on data in the User table.

B5: Append three columns, which derive from the main table, to B4’s subtable. The result during the first loop is:

B6:Concatenate B5’s result into B1. The operator “|” is equivalent to union function. When the loop is over, B1 will have collected all data the reporting needs, as shown below:

B7: Close data source connection explicitly.

A8: Return B1 to the reporting tool explicitly. The default execution is to return the result of the last cell.

Display data by different time units specified by parameter

Here is a reporting task that requires using a line graph to show the change of sales over a recent period. unitType is a report parameter, representing time units. If unitType="hour", show sales amount every five minutes in the past one hour. If unitType="day", show sales amount per hour during the past day. And show sales amount per day over the past one week if unitType="week". The data originates from the orders table in which Amount field contains order amount. t is used to reference the order time.

esProc script:

A1:An empty result set used to store the time sequences generated from B2-B4.

A2-B4:Generate different time sequences according to the report parameter unitType. B2 generates 12 time points, with an interval of 5 minutes between each other. B3 generates time points in one day, and B4 generates time points during one week.

A5:Loop through A1 to calculate the sales amount of each time interval. “~” represents the current member and “~[-1]" represents the previous one. In the case of unitType="day", a one-field result set containing 12 records will be generated.

A6:Return A5 to the reporting tool via JDBC. Then you can plot the graph to show the data.