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 functions in the past.
this confuses me a little bit. I don"t know how to design the table.
excuse me, are there any general basic standards for mongodb design? Or where can I find good examples for reference?
still exists. It mainly depends on your usage scenario. The concept of the corresponding data table in mongoDB is called collection,. A piece of data called document
you can look at this
can be designed like mysql to have a similar join concept called populate in mongo, for example, when a blog system user, a collection article, a collection user can associate one or more articles with a user query. Wait for populate to query it together
Project.updateOne(r, { $pull: { thunder2: { files: { _id: "5ab362d446f15936bcea7dd3" } } } }, function(err, data) { if (err) { res.send("") } else { ...
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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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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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...
assume a single document type: { "_id" : ObjectId("5a19403b421aa92332bc2b32"), "id" : "95957f4a9eab11e787f1509a4c4be0cd" "incre" :1 "city" "" } data volume, 90 mill...
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...
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...
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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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...
I tried to do this, but could not copy set initialization. ...
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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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