watch({ filter: { operationType: "insert", "fullDocument.type": "perennial", }, })) { // The change event will always represent a newly inserted perennial const { documentKey, fullDocument } = change; console.log(`new document: ${documentKey}`, fullDocument); }...
Mongodb 使用arrayfilter db.runCommand({ "update" : "ShortBatchOrder", "updates" : [{ "q" : { "_id" : "xxxxxxxx") }, "u" : { "$set":{"data.$[data].isDelete" : "1"} }, "upsert" : true, "arrayFilters" : [{ "data.orderCode" : { "$in" : ["xxxxxxx"] } }] }]...
Query an Array for an Element To query if the array field contains at leastoneelement with the specified value, use the filter{ <field>: <value> }where<value>is the element value. To query if the array field contains at leastelement with the specified value, construct a filter using the...
arrayFilters 阵列 可选。一个筛选器文档数组,确定要针对数组字段的更新操作修改哪些数组元素。 在更新文档中,使用 $[<identifier>] 筛选后的位置运算符来定义标识符,然后在数组筛选文档中引用该标识符。如果更新文档中未包含某一标识符,则无法获得该标识符的数组筛选文档。 <identifier> 必须以小写字母开头,且只能包...
var wordObjArr=new Array();for(var i=0; i<wordArr.length; i++){ try{ var word=wordArr[i].toLowerCase(); var vowelCnt= ("|"+word+"|").split(/[aeiou]/i).length-1; var consonantCnt= ("|"+word+"|").split(/[bcdfghjklmnpqrstvwxyz]/i).length-1; ...
db.students.find({‘address.state’ : ‘CA’}).toArray().length; //效率很低 1. 2. 3. 4. 5. group()对查询结果分组和SQL中group by函数类似 distinct()返回不重复值 四、索引 无疑,索引是一个数据库的关键能力,MongoDB 支持非常丰富的索引类型。利用这些索引,可以实现快速的数据查找,而索引的类型...
db.students.find({"age":19}).explain();{"queryPlanner":{"plannerVersion":1,"namespace":"mldn.students","indexFilterSet":false,"parsedQuery":{"age":{"$eq":19}},"winningPlan":{"stage":"FETCH","inputStage":{"stage":"IXSCAN","keyPattern":{"age":-1},"indexName":"age_-1","...
filter:采样的过滤规则。 在设置 Profiler 后,满足条件的慢请求将会被记录在 system.profile 表中,该表为一个 capped collection,可以通过 db.system.profile.find() 来过滤与查询慢请求的记录,举个例子: 代码语言:javascript 复制 >db.system.profile.find().pretty(){"op":"query",# 操作类型,可为command、...
import{Query}from"mingo";// input is either an Array or any iterable source (i.e Object{next:Function}) including ES6 generators.letcriteria={score:{$gt:10}};letquery=newQuery(criteria);// filter collection with find()letcursor=query.find(collection);// alternatively use shorthand// cursor...
schema"; const mySchema = new SimpleSchema( { name: String, }, { clean: { autoConvert: true, extendAutoValueContext: {}, filter: false, getAutoValues: true, removeEmptyStrings: true, removeNullsFromArrays: false, trimStrings: true, }, humanizeAutoLabels: false, requiredByDefault: true, ...