mongodb upsert 更新数组元素

使用MongoDB进行数据存储和查询的过程中，经常需要对数组元素进行更新操作。MongoDB提供了upsert操作，可以在更新数据时，如果数据不存在则插入新数据，如果数据存在则更新已有数据。接下来，我们将介绍如何使用upsert操作来更新数组元素，并提供相关的案例代码。

javascript
db.users.insertOne({name: "张三", skills: ["Java", "Python", "C++"]});
db.users.insertOne({name: "李四", skills: ["Java", "JavaScript", "HTML"]});
db.users.insertOne({name: "王五", skills: ["Python", "JavaScript", "CSS"]});

javascript
db.users.updateOne(
  {name: "张三", skills: "Java"}, 
  {$addToSet: {skills: "JavaScript"}}, 
  {upsert: true}
);

javascript
// 创建集合并插入示例数据
db.users.insertOne({name: "张三", skills: ["Java", "Python", "C++"]});
db.users.insertOne({name: "李四", skills: ["Java", "JavaScript", "HTML"]});
db.users.insertOne({name: "王五", skills: ["Python", "JavaScript", "CSS"]});
// 使用upsert操作更新数组元素
db.users.updateOne(
  {name: "张三", skills: "Java"}, 
  {$addToSet: {skills: "JavaScript"}}, 
  {upsert: true}
);