Resolved. My problem occurred because of the case-sensitive. I've read the source code of Solr-6.3 and found a code referencing metadata of databases, so I finally noticed that Oracle Database returns *UPPERCASE* letters from metadata.
As a correct setting, in the where clause of the query called by the child entity, it have to be written as follows. ## data-config.xml <document> <entity name="books" query="select book_id, title from books where deleted = 0" > - <entity name="contents" query="select book_id, content_id, content from contents where book_id = ${books.book_id} and deleted = 0" > + <entity name="contents" query="select book_id, content_id, content from contents where book_id = ${books.BOOK_ID} and deleted = 0" > </entity> </entity> </document> Only changing '${books.book_id}' to '${books_BOOK_ID}'. In my first Solr challenge, it took a while to solve it. Because I overlooked the small but important reasons. I hope this will be helpful for someone else. Kind, Keiichi -- View this message in context: http://lucene.472066.n3.nabble.com/DIH-do-not-work-Child-entity-cannot-refer-parent-s-id-tp4315023p4315444.html Sent from the Solr - User mailing list archive at Nabble.com.