How to set client request parameter as a offset in wso2esb - wso2

Question

i'm using wso2esb4.7.0 and wso2dss 3.1.0.My proxy service in esb allows to retrieve the perticular no of records from database.For that i have to use limit and offset in the query which is written in wso2dss.The query is as follows :
<sql>SELECT firstname, lastname FROM public.testlogin limit 5 offset ?</sql>
As per above query i have set the limit in query but offset is provded by client in request.My requirement is i have to retrieve the 5 records from offset of client requestNoq question is..How should i retrieve the offset which is in the client request.client request is as follows :
LogMediator To: /services/GetTaskDetails, MessageID: urn:uuid:caeaaebb-2239-4639-b1a2-094c22650de0, Direction: request, StartRecord = 6 Envelope: . . . .
here StartRecord is the offset in above request and i wanted to set it as offset in wso2 dss query please suggest something..

Answer 1

The query should work with the query and operation defined as follows:
`
<query id="SELECT" useConfig="MyDataSource">
<sql> SELECT firstname, lastname FROM public.testlogin limit 5 offset ? ;</sql>
<result element="patients" rowName="patient">
<element column="firstname" name="firstname" xsdType="string"/>
<element column="lastname" name="lastname" xsdType="string"/>
</result>
<param name="offset" optional="false" sqlType="INTEGER"/>
</query>
<operation name="getPatients">
<call-query href="SELECT">
<with-param name="offset" query-param="offset"/>
</call-query>
</operation>
`

Answer 2

You can modify the 'query' section in your dbs to set a input param. See the below example. It has a param name as employeeNumber. Which means, data services server will pickup the employeeNumber parameter from the SOAP request. You can modify appropriately. If there are more than one variable (ie. '?' symbols), then the ordering of the param is important.
The complete dbs sample can be found here in RDBMSSample.dbs.
<query id="employeesByNumberSQL" useConfig="default">
<sql>select * from Employees where employeeNumber = ?</sql>
<result element="employees" rowName="employee">
<element column="lastName" name="last-name" xsdType="string"/>
<element column="firstName" name="first-name" xsdType="string"/>
<element column="email" name="email" xsdType="string"/>
<element column="salary" name="salary" xsdType="double"/>
</result>
<param name="employeeNumber" ordinal="1" paramType="SCALAR" sqlType="INTEGER" type="IN"/>
</query>