Exact match in array (MongoDB)

Question

I have a collection in MongoDB that looks like this:

{
 "_id" : 1,
 "parent" : 1,
 "input" : [
     {
       "name" : "IAA1",
       "value" : "IAA1 Value3",
       "displayOrder" : 1
     },
     {
       "name" : "IAA2",
       "type" : "IAA2 Value4",
       "displayOrder" : 2
     }]
}

{
 "_id" : 2,
 "parent" : 1,
 "input" : [
    {
      "name" : "IAA1",
      "value" : "IAA1 Value3",
      "displayOrder" : 1
    },
    {
      "name" : "IAA2",
      "type" : "IAA2 Value4",
      "displayOrder" : 2
    },
    {
       "name" : "IAA3",
       "type" : "IAA2 Value4",
       "displayOrder" : 2
    } ]
}

What I need to do is, find only those documents that have all array elements that match the value of the name. For example:

{"input.name":{$all:["IAA1","IAA2","IAA3"]}}

This works fine and returns both documents, but this:

{"input.name":{$all:["IAA1","IAA2"]}}

Returns both documents as well. My requirements is that the 2nd query should only return the first document and not the second as it has an extra element with name:"IAA3".

The order of the elements in the array is not fixed I need to generate the query dynamically based on parent Id and what columns should be present.

$all is equivalent to $and so above query in $and as {"$and":[{"input.name":"IAA1"},{"input.name":"IAA2"}]} this match both documents because "IAA1","IAA2" contains in both documents. To find exact macth you should use aggregation . — Neo-coder
– Neo-coder, Commented Apr 30, 2015 at 6:27

Vishwas · Accepted Answer · 2015-04-30 06:42:12Z

2

You need to use combination of $size and $all operator to get desired result. size must be the number of parameters that you are using in $all. Here you must check size of input array to number of params in $all so that it will search given parameters ($all) only in those input array which size matches to number of params.

e.g. In sample Json you are using 2 params in $all so you must give $size of input as 2. In this case query will search only those input whose size is 2.

The query will be like -

db.collection.find({
"input.name": {
    $all: ["IAA1", "IAA2"]
},
"input": {
    $size: 2 // This is the number of param you pass in $all
}
}).pretty()

edited Apr 30, 2015 at 6:42

answered Apr 30, 2015 at 6:30

Vishwas

7,0777 gold badges46 silver badges70 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Vishwas Over a year ago

@Phoenix is it helpful to you??

user1211 · Accepted Answer · 2016-12-13 07:55:26Z

0

In order to have exact match, you should query just by the elements in the array. For eg:

{"input.name":["IAA1", "IAA2"]}

Refer here

answered Dec 13, 2016 at 7:55

user1211

1,5151 gold badge18 silver badges27 bronze badges

Collectives™ on Stack Overflow

Exact match in array (MongoDB)

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related