应对 mongodb修改多层数组对象时，一个$不够用。

栗子1：修改数组嵌套中的数据

一，原数据

{ "_id": ObjectId("5f7d88c342318e24c4003083"), "id": "123456", "arr": [ { "name": "nickchen", "condition": [ { "type": "phone", "contact": "159*******74" }, { "type": "email", "contact": "159*******74@163.com" } ] }, { "name": "hunter", "condition": [ { "type": "phone", "contact": "159*******74" }, { "type": "email", "contact": "159*******74@163.com" } ] } ] }

 二，SQL

//注意 $set条件与 arrayFilters条件 他们的数据层级关系。 db.lists.updateOne( {id:"123456"}, { $set:{ "arr.$[t].condition.$[val].contact":"123456789" } }, { arrayFilters:[{ "t.name":"nickchen", },{ "val.contact":"159*******74" }], multi:true } )

三，修改结果

{ "_id": ObjectId("5f7d88c342318e24c4003083"), "id": "123456", "arr": [ { "name": "nickchen", "condition": [ { "type": "phone", "contact": "123456789" }, { "type": "email", "contact": "159*******74@163.com" } ] }, { "name": "hunter", "condition": [ { "type": "phone", "contact": "159*******74" }, { "type": "email", "contact": "159*******74@163.com" } ] } ] }

栗子二：删除数组中的元素

一，原数据

{ "_id": ObjectId("5f7d829842318e24c4003082"), "id": "159789", "arr": [ { "name": "a1", "ins": [ "10", "11", "12" ] }, { "name": "a2", "ins": [ "13", "14", "15" ] } ] }

二，SQL

db.lists.updateOne( {"id":"159789"}, { $pull:{ "arr.$[t].ins":{$all:["10"]} } }, { arrayFilters:[{ "t.name":"a1", }], multi:true } )

三，修改结构

{ "_id": ObjectId("5f7d829842318e24c4003082"), "id": "159789", "arr": [ { "name": "a1", "ins": [ "11", "12" ] }, { "name": "a2", "ins": [ "13", "14", "15" ] } ] }