Can we change the XML structure of a file during file ingestion in MarkLogic using mlcp?

Question

I have a xml file to ingest in MarkLogic database where a new XML field has to be added. And the requirement is to add that XML field only during the mlcp import. Is this possible in MarkLogic using xquery?

XML file now -

<name>rashmita</name>
<employeeType>regular</employeeType>

XML to be changed -

<name>rashmita</name>
<employeeType>regular</employeeType>
<role>developer</role>

Answer 1

Yes, it is possible to modify the payload on ingest with MLCP.

Transforming Content During Ingestion

You can create an XQuery or Server-Side JavaScript function and install it on MarkLogic Server to transform and enrich content before inserting it into the database. Your function runs on MarkLogic Server.

Function Signature

A custom transformation is an XQuery function module that conforms to the following interface. Your function receives a single input document, described by $content, and can generate zero, one, or many output documents.

declare function yourNamespace:transform(
  $content as map:map,
  $context as map:map)
as map:map*

So, for your example (assuming that the actual docs are well-formed XML) could look something like:

module namespace example = "http://marklogic.com/example";
declare function example:transform(
  $content as map:map,
  $context as map:map
) as map:map*
{
  let $doc := map:get($content, "value")
  let $root := $doc/*
  let $_ :=
    if ($root)
    then 
      map:put($content, "value", 
        document { element {$root/name()} {$root/@*, $root/*, <role>developer</role>} })
    else ()
  return $content
};

Using a Custom Transformation

Once you install a custom transformation function on MarkLogic Server, you can apply it to your mlcp import or copy job using the following options:

• transform_module - The path to the module containing your transformation. Required.
• transform_namespace - The namespace of your transformation function. If omitted, no namespace is assumed.

An example invocation setting those parameters:

mlcp.sh import -mode local -host mlhost -port 8000 -username user -password password -input_file_path /space/mlcp-test/data -transform_module /example/mlcp-transform.xqy -transform_namespace "http://marklogic.com/example"