title: Why does the internal field names not match when working with list items using the SharePoint REST API?
body: <p>When I work with list items I need to use internal field names to set the field values. I have several fields of different data types, lets focus on two: 'Comment' (Multiple lines of Text) and 'Assigned' (Person or Group). I've created both myself.</p>
  
  <p>This is what I use to create/update list items, and it all works fine:
  <code>{ "__metadata" : { "type" : "SP.Data.ListItem" }, "Comment" : "Hello", "gomsId" : 215 }</code></p>
  
  <p>I knew to use "Comment" and "gomsId" by getting an existing list item and looking at the format I received.</p>
  
  <p>The problem is: The internal field name of 'Assigned' is <code>'goms'</code>. Not <code>'gomsId'</code>. So when I use <code>/_api/web/lists/getByTitle('ListName')/fields/getByTitle('Assigned')/internalname</code> to create list items it does not work. </p>
  
  <p>Why is the <code>'Id'</code> part appended for this field? Is it because of the data type? How do I know which fields will have <code>'Id'</code> appended and which will not?</p>