如何防止多个文档被添加到mongodb数据库

db.collection.createIndex({ field: 1 }, { unique: true })

db.createCollection("collection", {
  validator: {
    $jsonSchema: {
      bsonType: "object",
      properties: {
        field: {
          bsonType: "string",
          description: "Field must be unique"
        }
      },
      uniqueItems: true
    }
  }
})

session.startTransaction();

try {
  // 检查是否已存在相同的文档
  const existingDoc = db.collection.findOne({ field: "value" });

  if (!existingDoc) {
    // 插入文档
    db.collection.insertOne({ field: "value" });
  }

  session.commitTransaction();
} catch (error) {
  session.abortTransaction();
  throw error;
} finally {
  session.endSession();
}