I m not sure what assert is. Which god will answer it? here is an example of a connection to an official document const MongoClient = require( mongodb ).MongoClient; const assert = require( assert ); Connection URL const url = mongodb: lo...
if a field in a Mongo database is a JSON object, is it better to store it directly as an object or serialize it into a string and store it again? what are the advantages and disadvantages of the two methods? Is there any difference between performance an...
problem description There are two indexes in mongo, the first is a single-field index of the {_ id} field, and the second index is a composite index composed of {chat_id, _ id}. When I use the query db.collection.find ({ "chat_id ": ObjectId ( "* ")...
With WiredTiger, MongoDB utilizes both the WiredTiger internal cache and the filesystem cache. Starting in 3.4, the WiredTiger internal cache, by default, will use the larger of either: 50% of (RAM - 1 GB), or 256 MB. mongodb4.0 document, whi...
problem description for example, take the World Foreign language School as an example. When you use mongoose s $regex for fuzzy matching, you can match when you enter keywords such as the world and foreign languages, but when you enter keywords that ...
how can I set up an index query faster in mongodb? def open_spider(self, spider): self.Client = pymongo.MongoClient(self.MongodbHost, self.MongodbPort) self.Mongodb = self.Client[self.MongodbName] self.db = self.Mongodb[self.Mo...
1: when testing the performance of the interface, use mongostats to check the performance of the next mongo. Different document, of the same database are used, but the field values are not as expected. the first interface is find_one,document assuming ...
Last year, the title owner used node- express-mongodb to develop a simple internal website of the company. Yesterday, he upgraded the npm package, which led to mongodb.open reporting an error directly here, returning a 500error, and without any error pro...
def process_item(self, item, spider): print( ) print(item[ file_url ], item[ name ]) key_word = {"file_url":item[ file_url ] , "name": item[ name ]} res = self...
$Manage- > executeBulkWrite (); cannot judge the value returned by this method. What s going on ...
def process_item(self, item, spider): print( ) print(item[ file_url ], item[ name ]) key_word = {"file_url": item[ file_url ], "name": item[ name ]} res = self.db.find(key_word) if...
there are two collections data stores data, and attach stores attachments data and attach, one-to-many relationships. the ratio of data to attach is about 1:10, that is, a piece of data data, and there may be 10-50 pieces of data below. when data i...
mongodb, is used in node and listens to the service on the local port, which has been accessible normally until now, but has suddenly been inaccessible. Can t find out what the problem is connect mongoose mongoose.connect( mongodb: localhost cour...
there are two fields in the mongodb table: userId,status, where status has a value of 0 and 1, and a value of 2 . {userId:1, status: 0} {userId:1, status: 2} {userId:1, status: 2} {userId:2, status: 0} {userId:2, status: 1} {userId:2, status: 2} I want...
problem description I want to update the mongodb database and store an array with some deleted elements in mongodb, but when at least two threads perform this task at the same time, there is a second kind of update loss problem, such as the original a...
has anyone ever encountered a situation where the fields are uncertain when inserting into a database using Springboot JPA? for example, if you suddenly want to add a field and you have to change the entity class, is there any better way? now you can on...
problem description scrapy gives parse, different methods for the same url. Some can execute, and some cannot . the environmental background of the problems and what methods you have tried related codes urls=[ http: maoyan.com xseats 20180930015...
I have written a crawler. When writing the mongo class insert function, I want to add a judgment statement to avoid crawling data to load data repeatedly, but from the actual running situation, it is not feasible. Please take a look at the code first. ...
Database table information: var registerSchema = new mongoose.Schema({ email: String, name: String, password: String, img: String, hero: [], sex: String, hobby: String, signature: String }); data visualization: hero: ...
talbe name: server_groups, for example, has the following two pieces of data, and the field iplist is an array. There are multiple ranges stored in it, and I want to check whether a number falls within this range. If I query 150 and it falls into the fi...
mixed development: API request error in Android webview in Huawei Glory V8 Failed to load http: XXX API Login Password: Request header field Authorization is not allowed by Access-Control-Allow-Headers in preflight response. but access is normal in...
I want to add transition animation to the developed Vue project, with as few changes as possible, and provide cool effects. I wonder if you have any good plans? 1 transition components using Vue 2anime.js 3three.js at present, I can think of the ab...
when referencing popper.js, if packaging does not rule out popper.js, calling new PopperJS, an error will be reported let PopperJS = require( . popper ); let popper = new PopperJS(); PopperJS is not a constructor webpack.base.conf.js: ...
when you start nginx directly, it shows listening 0.0.0.0server_name 80 and then I change it to the ip, of the server at server_name and the result shows: failed (99: Cannot assign requested address) what is the problem? thank you ...
problem description: the data rendered by the foreground page is a table inserted by append, and another table is inserted in each row of td, which is equivalent to a nested table. ,; ,,??... The display of data is normal, all tables are n...