Implementation tutorial of MongoDB set field matching query method, mongodb Field

Implementation tutorial of MongoDB set field matching query method, mongodb Field

MongoDB is a distributed file storage-based database. This article describes how to perform matching queries on the fields integrated in MongoDB records.

1. Create a Test Database

use testdbdb.createUser(      {          "user":"root",          "pwd":"123456",          "roles":[{"role" : "readWrite", "db":"testdb"}]      }  ) db.auth(      {          "user":"root",          "pwd":"123456"      }  )

2. Insert test data. area_id is the set field.

db.member.insert([    {        "id" : 1,        "name" : "fdipzone",        "area_id" : [1,2,3],    },    {        "id" : 2,        "name" : "tom",        "area_id" : [3,4],    },    {        "id" : 3,        "name" : "polly",        "area_id" : [1,3,7],    },    {        "id" : 4,        "name" : "anslem",        "area_id" : [2,4,6],    },    {        "id" : 5,        "name" : "terry",        "area_id" : [4,5,9],    }])

Query inserted data

db.member.find();{ "_id" : ObjectId("59f589f5641e44b4c51cb770"), "id" : 1, "name" : "fdipzone", "area_id" : [ 1, 2, 3 ] }{ "_id" : ObjectId("59f589f5641e44b4c51cb771"), "id" : 2, "name" : "tom", "area_id" : [ 3, 4 ] }{ "_id" : ObjectId("59f589f5641e44b4c51cb772"), "id" : 3, "name" : "polly", "area_id" : [ 1, 3, 7 ] }{ "_id" : ObjectId("59f589f5641e44b4c51cb773"), "id" : 4, "name" : "anslem", "area_id" : [ 2, 4, 6 ] }{ "_id" : ObjectId("59f589f5641e44b4c51cb774"), "id" : 5, "name" : "terry", "area_id" : [ 4, 5, 9 ] }

3. Use $ in for query

Query records whose area_id contains 1

db.member.find({"area_id":{$in:[1]}});{ "_id" : ObjectId("59f589f5641e44b4c51cb770"), "id" : 1, "name" : "fdipzone", "area_id" : [ 1, 2, 3 ] }{ "_id" : ObjectId("59f589f5641e44b4c51cb772"), "id" : 3, "name" : "polly", "area_id" : [ 1, 3, 7 ] }

Note: $ in can only check whether each element in the set matches. If any element matches, a record is returned. It cannot check whether multiple elements are matched at the same time.

For example, to query records whose area_id contains both 2 and 4, use $ in to query only records whose IDs contain 2 or 4.

db.member.find({"area_id":{$in:[2,4]}});{ "_id" : ObjectId("59f58ddfa874fe2b3da340bf"), "id" : 1, "name" : "fdipzone", "area_id" : [ 1, 2, 3 ] }{ "_id" : ObjectId("59f58ddfa874fe2b3da340c0"), "id" : 2, "name" : "tom", "area_id" : [ 3, 4 ] }{ "_id" : ObjectId("59f58ddfa874fe2b3da340c2"), "id" : 4, "name" : "anslem", "area_id" : [ 2, 4, 6 ] }{ "_id" : ObjectId("59f58ddfa874fe2b3da340c3"), "id" : 5, "name" : "terry", "area_id" : [ 4, 5, 9 ] }

4. Use $ all for query

$ All: checks whether multiple elements are matched at the same time.

Query records whose area_id contains both 2 and 4

db.member.find({"area_id":{$all:[2,4]}});{ "_id" : ObjectId("59f58ddfa874fe2b3da340c2"), "id" : 4, "name" : "anslem", "area_id" : [ 2, 4, 6 ] }