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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"best practice to load many relations ids from database","articleBody":"I try to implement a solution that uses graphql-java and dataloader over a database.\r\n\r\nI would like to know the best pratice to load a many relations when the nested ids required a database query.\r\n\r\nin the documentation example, imagine that we replace `starWarsCharacter.getFriendsIds()` by a database query `getFriendIdsFromDB(starWarsCharacter)`. \r\nThe `friendsDataFetcher` would looks like :\r\n```\r\n DataFetcher friendsDataFetcher = new DataFetcher() {\r\n            @Override\r\n            public Object get(DataFetchingEnvironment environment) {\r\n                StarWarsCharacter starWarsCharacter = environment.getSource();\r\n                List\u003cString\u003e friendIds = getFriendIdsFromDB(starWarsCharacter);\r\n                return characterDataLoader.loadMany(friendIds);\r\n            }\r\n        };\r\n```\r\nIn this case it generates again a N+1 fetch problem. For each Character we have to query for the friends ids. \r\n\r\nHow to efficiently manage that case with the dataloader?","author":{"url":"https://github.com/vincentlejeune","@type":"Person","name":"vincentlejeune"},"datePublished":"2018-10-29T13:06:13.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/34/java-dataloader/issues/34"}