const dbName = 'mydb'; MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, function(err, client) { if (err) throw err; const db = client.db(dbName); const usersCollection = db.collection('users'); // 插入一个嵌套子document usersCollection.insertOne({ name:...
db.userInfo.find() || show collections //相当于:select* from userInfo; 1. ---精确查找 db.userInfo.find({age: 22}) //查询age = 22的记录 db.userInfo.find({"score.math": 98}) //查询其中某个对象下的数据,必须带引号 1. 2. ---多条件查找 db.userInfo.find({age: {$gte: 23, $lte...
importjava.utilimportcom.mongodb.{BasicDBObject,MongoClient,MongoClientURI}importorg.slf4j.LoggerFactoryobjectMongoUtil{defqueryDocCntAndFieldCnt(url:String,userName:String,password:String,dbName:String,collectionName:String):(Long,Int)={vardocCount:Long=0LvarfieldCount:Int=0varmongodbInputUri=urlif(us...
their policy, the insurance company keeps a record of the policy changes over time. The company uses theDocument Versioningpattern to track policy revisions by storing each update in a separate document. Historical data is stored in a separate collection, and does not impact queries on current ...
MongoDB's flexible data model gives you multiple options to map relationships between different entities in your schema. Generally, your choice of data model depends on whether you want to embed related data in the same collection or use references to connect related data that exists in separate...
In this tutorial, we’ll look at performing query operations using the Document ID in MongoDB. MongoDB provides a find operator to query documents from a collection. In this tutorial, we’ll first look at querying documents using Document ID in the MongoDB Shell query and then use the ...
collection.insert(new BasicDBObject().append("employeeId", i).append("employeeName", "TestEmployee_"+i)); } } Now run our examples and fetch the data on different scenarios. 1. MongoDB find() – Select all documents from a collection private static void selectAllRecordsFromACollection(DB...
A collection of original, innovative ideas and algorithms towards Advanced Literate Machinery. This project is maintained by the OCR Team in the Language Technology Lab, Tongyi Lab, Alibaba Group. ocrcomputer-visionartificial-intelligencetext-recognitiondocumenttext-detectiondocument-analysisend-to-end-ocrmu...
mongoDB-Cannot change the size of a document in a capped collection: 简单记录一下: 造成该问题的原因是集合被设置成了 固定集合 。固定集合的数据不能被修改。只能查找-删除-再插入
固定集合的数据不能被修改。只能查找-删除-再插入,也就是创建集合的时候设置了capped参数为true 解决: 创建集合的时候capped为false或者不写这个参数,默认为false 参考: https://www.solidsyntax.be/2016/03/26/MongoDB-Cannot-change-the-size-of-a-document-in-a-capped-collection/...