Recent questions tagged mongo

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mongo db query for passing value from outer query into inner query

i have a work collection, with fields work_id, work_ref, sequence, etc. I need a query for mongodb for its sql ... -db-query-for-passing-value-from-outer-query-into-inner-query...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

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mongo shell - How do I convert an array of objects / subdocuments to an array of strings in a MongoDB Aggregation pipeline?

I have documents with the following structure { "_id":{"$oid":"..."}, "work_type": "ASSIGNMENT", "materials": [ ... -an-array-of-objects-subdocuments-to-an-array-of-strings-in-a...

asked Oct 7, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.2k views

1 answer

mongo insert一条记录，但某些数据未插入

用node写了个服务提供一个接口，供调用方传入参数后，对参数进行封装，在 mongo 里面 insert 一条记录，现发现某几个字段更新不进去代码类似于以下 const db = mongodb.collection('collection_name') ... 更新后的文档，返回结果是有 c 值的，但 mongo 里面依然没有c字段值求大神解答！！！...

asked Feb 5, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mongo 查询是否存在子节点

集合tab1 有字段 id pid name, 示例数据如下，需要查询name=张三且没有 pid=id 的数据不知道怎么写返回的结果应该是id 等于 1和3的行 SQL: select * from tab1 where ... t where t.pid=tab1.id) id pid name 1 张三 2 张三 3 2 张三 4 李四...

asked Jan 29, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.1k views

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mongo 运行的时候卡住

运行sudo mongod 的时候卡在这里，等了很久没有结果 2020-05-08T16:13:31.446+0800 I CONTROL [main] Automatically ... [ftdc] Marking collection local.oplog.rs as collection version: <unsharded>...

asked Jan 29, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

1.1k views

1 answer

mongo 查询是否存在子节点

集合tab1 有字段 id pid name, 示例数据如下，需要查询name=张三且没有 pid=id 的数据不知道怎么写返回的结果应该是id 等于 1和3的行 SQL: select * from tab1 where ... t where t.pid=tab1.id) id pid name 1 张三 2 张三 3 2 张三 4 李四...

asked Jan 29, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

968 views

1 answer

mongo 运行的时候卡住

运行sudo mongod 的时候卡在这里，等了很久没有结果 2020-05-08T16:13:31.446+0800 I CONTROL [main] Automatically ... [ftdc] Marking collection local.oplog.rs as collection version: <unsharded>...

asked Jan 29, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

1.2k views

1 answer

mongo mgo v2中聚合查询中怎么使用动态条件？

where := bson.M{"$match": bson.M{"user_id": userId, "bank_id": bankId, "knowledge_points": bson.M{"$in": Knowledge}, "difficulty" ... difficulty": difficulty是可选项，如果有值才会进行匹配，请问该怎么写？...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

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1.0k views

1 answer

mongo 游标丢失

在分片集群中，报游标超时。同样的程序，在副本集集群中，是正常的。已经尝试增加游标超时时间，batchSize就算是设置成1也会过十几分钟报错。还可能是什么原因呢？...

asked Jan 27, 2021 in Technique[技术] by 深蓝 (71.8m points)

0 votes

3.9k views

1 answer

mongo array字段维护有限多少个

文档模型为 { "_id" : ObjectId("5fda6ae8bf760f494532a9fa"), "pairs": [ { "value": "ip", "time": ISODate("2020-12-17T04:15:33.000+08:00") ... pair中value需要唯一，怎么从数据库角度比较优雅的维护长度限定为最多100个pair...

asked Jan 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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