In some case you need to store group of related information such as the author and their affiliation as appear in the publication "header", the project title, grantno, funding program related to the publication or the Journal Title, the ISSN, the E-ISSN, etc.

In the first two examples the group of metadata is repeatable, this mean that we need to couple the first value in the "author names" with the first value in the "affiliations" etc.
Generally, in DSpace you want to solve these scenario using additional entities to link with the item. This is of course the proper way to manage the use case but supporting in the system additional entities is not always an option or possible at all the extend. In addition, you could want to allow the submitter to input proper rich information during the item submission to be saved / consolidated after in a separate entity.

In other case, also if the information are related to an external entities as in the example of the author affiliation, these information are also needed to be stored / freeze on the item level. For instance you could be interested to know which institutions are listed on a publication as affiliations regardless of the institution that is linked "now" to each authors. Also if you assume to know exactly the affiliation of each author at any time (complete career track) you will be unable to know which institution he has listed in the publication signature (this because the date to use is partially uncertain and also because the author could have made a choice between several institutions depending on the one that have actually supported his publication work).

To meet such requirement, DSpace allows you to greate groups of nested metadata in the submission for and the item page.

The default group in submission will become a nested form and will be opened in a modal, to isolate the form and create connections between groups of metadata.

Required Configuration

To use nested metadata groups, update your submission-forms.xml and item-submission.xml:

1. Define a Step in item-submission.xml

<step-definition id="publicationStepGroup" mandatory="true">
    <heading>submit.progressbar.describe.stepone</heading>
    <processing-class>org.dspace.app.rest.submit.step.DescribeStep</processing-class>
    <type>submission-form</type>
</step-definition>

Then reference it in a submission process:

<submission-process name="publication-submission">
    <step id="collection"/>
    <step id="publicationStepGroup"/>
</submission-process>

2. Define Grouped Forms in submission-forms.xml

For group input type (used with relation-field), create a main form and child forms following the naming convention formName-dc-element-qualifier:

Main form (publicationStepGroup):

<form name="publicationStepGroup">
    <row>
        <relation-field>
            <relationship-type>isAuthorOfPublication</relationship-type>
            <search-configuration>person</search-configuration>
            <repeatable>true</repeatable>
            <label>Author</label>
            <hint>Enter the author's name.</hint>
            <linked-metadata-field>
                <dc-schema>dc</dc-schema>
                <dc-element>contributor</dc-element>
                <dc-qualifier>author</dc-qualifier>
                <input-type>group</input-type>
            </linked-metadata-field>
            <externalsources>orcid</externalsources>
        </relation-field>
    </row>
</form>

Child form (publicationStepGroup-dc-contributor-author):

<form name="publicationStepGroup-dc-contributor-author">
    <row>
        <field>
            <dc-schema>dc</dc-schema>
            <dc-element>contributor</dc-element>
            <dc-qualifier>author</dc-qualifier>
            <label>Author</label>
            <input-type>onebox</input-type>
            <repeatable>false</repeatable>
            <required>You must enter at least the author.</required>
            <hint>Enter the names of the authors.</hint>
        </field>
    </row>
    <row>
        <field>
            <dc-schema>oairecerif</dc-schema>
            <dc-element>author</dc-element>
            <dc-qualifier>affiliation</dc-qualifier>
            <label>Affiliation</label>
            <input-type>onebox</input-type>
            <repeatable>false</repeatable>
            <required />
            <hint>Enter the affiliation of the author.</hint>
        </field>
    </row>
</form>

For inline-group input type (simple field grouping):

<form name="publicationStepGroup">
    <row>
        <field>
            <dc-schema>dc</dc-schema>
            <dc-element>contributor</dc-element>
            <dc-qualifier>editor</dc-qualifier>
            <repeatable>false</repeatable>
            <label>Editor</label>
            <input-type>inline-group</input-type>
            <hint>The editors of this publication.</hint>
            <required>You must enter at least the author.</required>
        </field>
    </row>
</form>

Note: Child forms must be named using the pattern: {parentFormName}-{dc-element}-{dc-qualifier} for the group input type to resolve correctly.

A new group type called inline-group has been added to mantain the groups inside the main form and not in a modal, follows and example of config:

Please note that the inline-group as a limitation: all the fields needs to be configured inside one tag.
If you want to achieve a display on multiple rows, it can be don through styling, adding for example to each field the style tag as follows: <style>col-12</style>
This is a known limitation and should be added to the documentation as such.

 <row>
              <field>
                <dc-schema>dc</dc-schema>
                <dc-element>contributor</dc-element>
                <dc-qualifier>editor</dc-qualifier>
                <label>Editor group</label>
                <input-type>inline-group</input-type>
                <repeatable>true</repeatable>
                <required />
                <hint>Add the editor of this publication</hint>
              </field>
</row>

<form name="publicationStep-dc-contributor-editor">
          <row>
            <field>
              <dc-schema>dc</dc-schema>
              <dc-element>contributor</dc-element>
              <dc-qualifier>editor</dc-qualifier>
              <label>Editor</label>
              <input-type>onebox</input-type>
              <repeatable>false</repeatable>
              <required>You must enter at least the author.</required>
              <hint>The editors of this publication.</hint>
            </field>
            <field>
              <dc-schema>oairecerif</dc-schema>
              <dc-element>editor</dc-element>
              <dc-qualifier>affiliation</dc-qualifier>
              <label>Affiliation</label>
              <input-type>onebox</input-type>
              <repeatable>false</repeatable>
              <required />
              <hint>Enter the affiliation of the editor as stated on the publication.</hint>
            </field>
          </row>
</form>

Please note that is not possible to add repeatable fields inside the nested forms, this would result in errors in the UI breaking the form. This is a known limitation and should be added to the documentation as such.

Input type specific configuration, as the regex, should be added inside the nested form configuration, as they don't work on input types which represent nested forms. (not an actual control in the form).

Note: For inline groups is possible to configure an additional button with the property showInlineGroupDuplicateButton , which if true, will display under the form a button to duplicate the whole section, metadata values included.