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Mongodb update level 3 or above cannot be deleted
Project.updateOne(r, {
$pull: {
thunder2: {
files: {
_id: "5ab362d446f15936bcea7dd3"
}
}
}
}, function(err, data) {
if (err) {
res.send("")
} else {
...
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How to add mongodb service under Windows 10?
the previous command is as follows:
mongod --logpath C: mydatabase logs.txt --logappend --dbpath C: mydatabase --serviceName MongoDB --install
however, there is no prompt on the command line after entering the carriage enter, and the service has ...
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How does php MongoDB turn ObjectId into string
the query data is printed to see that _ id is objectID,. If it is directly converted to json,_id, it will be empty. Can you change objectID to string, and then to json? ...
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What is the Virtual of mongoose?
Virtual properties are document properties that you can get and set but that do not get persisted to MongoDB.
I don t quite understand this sentence. Please do not translate. I hope you can explain it in your own words. It is better to have examples. ...
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It is invalid for MongoDB, to use the configuration file to modify the database path?!
first of all, according to the description of the official document, the configuration file is created and the database path is modified. The content of the configuration file mongo.config is as follows:
systemLog:
destination: file
path: I: ...
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Mongodb cannot be started under mac
suddenly became interested in mongodb, installed and started with brew according to the rookie tutorial, but showed "waiting for connections on port 27017 " for a long time, then
as a front-end younger brother who still has a narrow range of knowle...
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What is the difference in the way mongodb starts?
Mode 1: mongod Command Mode 2: brew services start mongodb Command start
what s the difference between the two ways of starting? why are there two ways?
...
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About mongodb doing document management?
the company recently has a project, the main function is to manage documents, such as on the web page to view the contents of the document, and can be modified, you can also download the document to export in word format, the most important thing is to r...
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Mongdb 90,000,000 data query fetches
assume a single document type:
{
"_id" : ObjectId("5a19403b421aa92332bc2b32"),
"id" : "95957f4a9eab11e787f1509a4c4be0cd"
"incre" :1
"city" ""
}
data volume, 90 mill...
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Explain this custom mongoose schema method
var animalSchema = new Schema({ name: String, type: String });
animalSchema.methods.findSimilarTypes = function(cb) {
return this.model( Animal ).find({ type: this.type }, cb);
};
var Animal = mongoose.model( Animal , animalSchema);
var dog = new A...
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MongoDB link failed mongo "exception: connect failed"
the computer is a WIN 10 system I follow this tutorial to install mongoDB, http: www.runoob.com mongodb.
but as soon as you enter the mongo link. Just report this error
has been reinstalled several times, but it has not been solved. also chan...
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Can't connect to the server's mongdb database!
ip and port are OK on the server!
bind_ip 0.0.0.0
ip
ask the boss to have a look. No, no, no. It s okay to pay for an answer!
...
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How to use mongodb for ifelse Operation in spring boot
data stores a field type (as an enumeration). When querying, it needs to be processed separately by using ifelse or switch, for example, 1 is converted to normal. I ve implemented it with the MongoDB statement, but how do I handle it in the springboot ...
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How does mongodb use aggregate to count the total number of non-duplicated fields in a group?
there is data like this:
I want to use aggregate to group group by p, and then count the sum of ac, cc in each province, which can be done. The question is: I want to count the total number of tc in each province (do not repeat)? For example, Fujia...
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Whether the mongodb replication set can be taken from the disk and taken out separately to make a new mongodb server.
I tried to do this, but could not copy set initialization. ...
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Python uses pymongo to connect to the local database prompt to actively reject?
the problem is like a question. I ll describe the details in detail. asked the same question on Zhihu
when I was self-taught python crawler, I came into contact with MongoDB, to install according to the URL given by rookie tutorial . Visual obser...
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A subset of a subset of mongoose queries
first of all, the models of my mongoose is as follows:
var clubsSchema = new mongoose.Schema({
"clubCreatetime": String,
"clubCreater": String,
"clubName": String,
"clubDescription": String,
&...
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The loop of cursor in pyMongo is very slow, is there any effective way to solve it?
there are 200000 data in the data, and each data has a typical list of words of 5000 length [{aVl1}, {bju 2},.], and typical dictionaries of 5000 length {{aRom 1}, {bjr 2},.}, use pyMongo to find100 data, the traversal of cursor is particularly slow, is...
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What is mongoose streaming??
You can stream query results from MongoDB. You need to call the Query-sharpcursor () function to return an instance of QueryCursor.
Please do not translate directly. I want to know what cursor is and what stream is, and why I use it, thank you!
...
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Ask mongodb this kind of nosql database design, are there any basic principles?
mongodb doesn t seem to have the join functionality of sql. Reducing the redundancy of individual tables does not seem to make sense and affects query efficiency. and mongodb also has storage formats such as lists, which can achieve different function...
