Spring-data-mongodb：mongoTemplate - 从文档集合中的数组中删除元素

Question

假设我有一个包含以下文档的集合：

{name: "a", preferences: ["apples","oranges","bananas"]}    
{name: "b", preferences: ["apricots","oranges","strawberries"]}
{name: "c", preferences: ["oranges","plums"]}
{name: "d", preferences: ["apples","plums","oranges"]}
{name: "e", preferences: ["strawberries","bananas"]}

现在已经没有橙子了，所以我想从所有文档中删除它们，最后得到：

{name: "a", preferences: ["apples","bananas"]}    
{name: "b", preferences: ["apricots","strawberries"]}
{name: "c", preferences: ["plums"]}
{name: "d", preferences: ["apples","plums"]}
{name: "e", preferences: ["strawberries","bananas"]}

我一直想知道，使用 Spring的mongoTemplate ，是否有任何直接的方法可以做到这一点，除了明显的（并且，我猜，效率低，因为集合可能是巨大的迭代方式？谢谢你的帮助。

Answer 1

这样的事情会做

Update update = new Update();
new Update().pull("preferences", "oranges");
Criteria criteria = Criteria.where("preferences").elemMatch(Criteria.where("oranges").exists(true));// Use this if you don't want to do the above update for all documents.

mongoTemplate.updateMulti(new Query(criteria), update, "collection_name");