Jasper(Soft) : Use multiple Oracle-Database datasources for single report - jasper-reports

Question

I have a Jasper server which has a few templates in one of the folders. I also have an application with a button, and when you click the button it will show a list of all the jasper documents from that folder.
Currently a single parameter (an id) is used in all these Jasper reports, which each use their own query based on what they need.
Now I've added a new jasper template, which has to use a different datasource based on a year parameter, in this same folder.
What I could do is just add this year to the parameter list I send to Jasper for every template in this folder, in which case it will use the id for all the existing templates, and the year for this new one.
However, I prefer to not deploy a new version of this application for the sake of an added jasper template, so I'd like to do the following instead:
Use the parameter id with datasource 1 to query for the year I need
Use this year as parameter with datasource 2 to create the query for the actual jasper report template
So my question: Is this possible? Can a single jasper report have multiple oracle-DB connection datasources? And can I then query for the year in one datasource, to use in the other datasource?
EDIT:
Although the duplicated link gave me a good direction, I'm currently again stuck with the same problem.
What I've done is the following:
I've created the main-report which contains nothing more than a sub-report, and has an id parameter (which will be used to query for the field YEAR in datasource_host_main).
I've created a sub-report with the actual text and lists and such based on a query on datasource_host_sub (with a year parameter).
Here is the code for Main:
<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.3.1.final using JasperReports Library version 6.3.1 -->
<!-- 2017-04-10T17:05:30 -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="Main" language="groovy" pageWidth="595" pageHeight="842" columnWidth="515" leftMargin="40" rightMargin="40" topMargin="20" bottomMargin="20" uuid="3830f8f8-db92-4043-bcbe-4af8cbc24623">
<property name="com.jaspersoft.studio.data.defaultdataadapter" value="datasource_host_main"/>
<property name="com.jaspersoft.studio.unit." value="pixel"/>
<property name="com.jaspersoft.studio.unit.pageHeight" value="pixel"/>
<property name="com.jaspersoft.studio.unit.pageWidth" value="pixel"/>
<property name="com.jaspersoft.studio.unit.topMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.bottomMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.leftMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.rightMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.columnWidth" value="pixel"/>
<property name="com.jaspersoft.studio.unit.columnSpacing" value="pixel"/>
<property name="com.jaspersoft.studio.data.sql.tables" value=""/>
<property name="ireport.jasperserver.url" value="my_jasper_server_host/jasperserver-pro/"/>
<property name="ireport.jasperserver.user" value="superuser|"/>
<property name="ireport.jasperserver.reportUnit" value="/users/user_1/reports/Systeem/Main"/>
<property name="ireport.jasperserver.report.resource" value="/users/user_1/reports/Systeem/Main_files/main.jrxml"/>
<parameter name="id_parameter" class="java.lang.Integer">
<parameterDescription><![CDATA[id_parameter]]></parameterDescription>
<defaultValueExpression><![CDATA[1]]></defaultValueExpression>
</parameter>
<queryString>
<![CDATA[select dataYear
from MY_TABLE
where id = $P{id_parameter}]]>
</queryString>
<field name="dataYear" class="java.lang.String"/>
<background>
<band splitType="Stretch"/>
</background>
<title>
<band height="28" splitType="Stretch"/>
</title>
<detail>
<band height="210" splitType="Stretch">
<subreport>
<reportElement x="6" y="10" width="504" height="200" uuid="e130bc4e-f114-4bd1-b408-dc9ce261b18c"/>
<subreportParameter name="dataYear">
<subreportParameterExpression><![CDATA[$F{dataYear}]]></subreportParameterExpression>
</subreportParameter>
<!-- This below doesn't work: I want to connect to a different datasource in the sub-report -->
<connectionExpression><![CDATA[oracle.jdbc.driver.OracleDriver.getConnection("jdbc:oracle:thin:#datasource_host_sub:1234:ab", "USERNAME", "PASSWORD")]]></connectionExpression>
<subreportExpression><![CDATA["subreport.jrxml"]]></subreportExpression>
</subreport>
</band>
</detail>
<columnFooter>
<band/>
</columnFooter>
<pageFooter>
<band height="39"/>
</pageFooter>
</jasperReport>
Subreport:
<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.3.1.final using JasperReports Library version 6.3.1 -->
<!-- 2017-04-10T16:37:07 -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="subreport" language="groovy" pageWidth="595" pageHeight="842" columnWidth="515" leftMargin="40" rightMargin="40" topMargin="20" bottomMargin="20" uuid="3830f8f8-db92-4043-bcbe-4af8cbc24623">
<property name="com.jaspersoft.studio.data.defaultdataadapter" value="datasource_host_sub"/>
<property name="com.jaspersoft.studio.unit." value="pixel"/>
<property name="com.jaspersoft.studio.unit.pageHeight" value="pixel"/>
<property name="com.jaspersoft.studio.unit.pageWidth" value="pixel"/>
<property name="com.jaspersoft.studio.unit.topMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.bottomMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.leftMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.rightMargin" value="pixel"/>
<property name="com.jaspersoft.studio.unit.columnWidth" value="pixel"/>
<property name="com.jaspersoft.studio.unit.columnSpacing" value="pixel"/>
<property name="com.jaspersoft.studio.data.sql.tables" value=""/>
<property name="ireport.jasperserver.url" value="my_jasper_server_host/jasperserver-pro/"/>
<property name="ireport.jasperserver.user" value="superuser|"/>
<property name="ireport.jasperserver.reportUnit" value="/users/user_1/reports/Systeem/Main"/>
<property name="ireport.jasperserver.report.resource" value="/users/user_1/reports/Systeem/Main_files/subreport.jrxml"/>
<parameter name="dataYear" class="java.lang.Integer">
<parameterDescription><![CDATA[dataYear]]></parameterDescription>
<defaultValueExpression><![CDATA[YEAR( )]]></defaultValueExpression>
</parameter>
<queryString>
<![CDATA[select NOTES
from MY_TABLE
where extract(year from to_date(DATE, 'dd-MM-yy')) = $P{dataYear}]]>
</queryString>
<field name="NOTES" class="java.lang.String"/>
<background>
<band splitType="Stretch"/>
</background>
<title>
<band height="140" splitType="Stretch"/>
</title>
<detail>
<band height="60" splitType="Stretch">
<textField>
<reportElement x="0" y="18" width="510" height="30" uuid="ed29caa8-a839-4457-a270-68bfedcfadb8"/>
<textFieldExpression><![CDATA["Test: " + $F{NOTES}]]></textFieldExpression>
</textField>
</band>
</detail>
<columnFooter>
<band/>
</columnFooter>
<pageFooter>
<band height="20"/>
</pageFooter>
</jasperReport>
The Main report uses datasource_host_main, and the sub-report uses datasource_host_sub. Because a Jasper report has only one .properties file with one jasperDatasourceUri, I can only define datasource_host_main. But how can I define datasource_host_sub for the sub-report? As you can see in the mainreport code I tried to do something like this:
<connectionExpression><![CDATA[oracle.jdbc.driver.OracleDriver.getConnection("jdbc:oracle:thin:#datasource_host_sub:1234:ab", "USERNAME", "PASSWORD")]]></connectionExpression>
But unfortunately it gives this error:
net.sf.jasperreports.engine.fill.JRExpressionEvalException: Error evaluating expression for source text: oracle.jdbc.driver.OracleDriver.getConnection("jdbc:oracle:thin#datasource_host_sub:1234:ab", "USERNAME", "PASSWORD")
What should I put here instead to make it work (both are Oracle databases), and is it even possible to do it like this?
As I said in my original question:
Can a single jasper report have multiple oracle-DB connection datasources? And can I then query for the year in one datasource, to use in the other datasource?

Answer 1

In JasperReports Server you can use a different data source/DB connection for a subreport or subdataset by setting the com.jaspersoft.jrs.data.source property as the data source repository path at (sub)report or subdataset level.
In your case, you would have the report unit use a data source that connects to datasource_host_main, and the following property in the subreport JRXML:
<property name="com.jaspersoft.jrs.data.source" value="/datasources/host_sub_datasource"/>
where /datasources/host_sub_datasource is the repository path of a data source resource that connects to datasource_host_sub.
Outside JasperReports Server, the same thing can be achieved with data adapters (which replace JasperReports Server data sources). The property to set is net.sf.jasperreports.data.adapter, and it needs to point to a path/resource/URI for a data adapter XML file.