I have a problem. I want to automatically give a current time when I insert a piece of data for the first time, because I need to use upsert to ensure efficiency, so I can"t process it one by one with find. How can I set a default value for this? Checked the mongodb does not seem to support, ask the great god to solve the doubt.
db.<coll>.update({}, {$set: {}, $setOnInsert: {date: new Date()}}, {upsert: true});plus $setOnInsert indicates that this field is only available when inserted. Unlike a relational database, this time comes from your application, not the default value added to the database.
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 ...
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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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...
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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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I tried to do this, but could not copy set initialization. ...
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