我有一个学生文档列表,其结构如下:
{
"_id" : 0,
"name" : "aimee Zank",
"scores" : [
{
"type" : "exam",
"score" : 1.463179736705023
},
{
"type" : "quiz",
"score" : 11.78273309957772
},
{
"type" : "homework",
"score" : 6.676176060654615
},
{
"type" : "homework",
"score" : 35.8740349954354
}
]
}
如你所见,每个学生都有一个包含4个分数的列表。我需要删除每个学生文档的最低“家庭作业”分数。每个学生有2个条目表示"homewok“类型的分数(4个元素数组中的最后2个条目)。分数类型的模式和顺序是一致的,并且对所有学生都具有相同的模式,感谢您的帮助。
这就是我到目前为止一直在努力实现的:
DBCursor cursor = collection.find();
try {
while(cursor.hasNext()) {
BasicDBObject doc = (BasicDBObject) cursor.next();
BasicDBList scoreList = (BasicDBList) doc.get("scores");
BasicDBObject hw1 = (BasicDBObject) scoreList.get("2");
double hw1Score = hw1.getDouble("score");
BasicDBObject hw2 = (BasicDBObject) scoreList.get("3");
double hw2Score = hw2.getDouble("score");
if (hw1Score > hw2Score) {
BasicDBObject update = new BasicDBObject("scores.score", hw2Score);
collection.update(doc, new BasicDBObject("$pull",update));
} else {
BasicDBObject update = new BasicDBObject("scores.score", hw1Score);
collection.update(doc, new BasicDBObject("$pull",update));
}
System.out.println(doc);
}
} finally {
cursor.close();
}
}
https://stackoverflow.com/questions/28071078
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