Moved from Arquillian to Teiid forum.

invokeHTTP as name suggests is to invoke a http call, not a SQL call. See the documentation at Web Services Translator · Teiid Documentation

An example VDB would be like to read an XML file

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vdb name="webservice" version="1">
    <description>Shows how to call Web Services</description>
    
    <model name="CustomerSource">
        <source name="webservice" translator-name="ws" connection-jndi-name="java:/webDS"/>
    </model>
    
      <model name="Customers" type="VIRTUAL">
        <metadata type="DDL"><![CDATA[        
              CREATE  VIEW CustomersView (
               customernumber varchar(100) PRIMARY KEY, customername varchar(200), contactlastname varchar(100),  contactfirstname varchar(100))
              AS
               SELECT
                     A.customernumber, A.customername, A.contactlastname, A.contactfirstname
               FROM
                (EXEC CustomerSource.invokeHttp('GET', null, 'http://localhost:8080/CustomerRESTWebSvc/MyRESTApplication/customerList', 'TRUE')) AS f,
                XMLTABLE('/customers/customer' PASSING XMLPARSE(DOCUMENT f.result) COLUMNS customernumber string PATH 'customernumber/text()',
                customername string PATH 'customername/text()', contactlastname string PATH 'contactlastname/text()', contactfirstname string PATH 'contactfirstname/text()') AS A;          
        ]]>
        </metadata>
    </model>
</vdb>

The URL in the invokeHttp can be relative or absolute. If it is relative then the base uri needs to be defined in the data source defined by "java:/webDS" in above example. For creating the data source see example here Web Service Data Sources · Teiid Documentation

if the payload is JSON, then wrap the response with JSONTOXML function to convert into XML, then use above to parse into tabular results.

HTH

Ramesh..

>Here my requirement is to pass the sql query to REST server . Is it achievable from VDB ?

absolutely

>How to pass the above sql query  as request object ?

depends on how you design your rest service, is it a GET or POST etc.

>I am using this procedure (invokeHttP) in my custom Translator ,

Not in the exception stack you provided above, you are calling it directly from JDBC layer. In that case, you need to strictly follow the invokeHTTP calling semantics.

If you want to write custom translator, then you would need to extend "ws" translator and write your own. See examples of "swagger" and "odata4", "odata" as how they extended and using the existing "ws" translator to issue "http" calls.

> in this case parsing error is coming . It is not allowing String value in in request parameter ( EMP_NAME='Dinesh' ) . If I am passing any other type long/int (like EMP_ID=10)  it is working .

If you nest a single quote in a string literal it needs to be escaped with another single quote ''Dinesh''

It depends upon how you defined transformation query of the EMPLOYEE view. It is not automatically passed. A View gets executed at the Teiid engine level, so what is in transformation SQL matters. If view is based on some source table in custom translator, then if one executes the view, you will see relevant access to that source table, which could be a invokeHttp call in your translator, with full freedom to send whatever you want.