Spring MongoDB Data elemMatch Simple

Question

{ _id: 1, results: [ "tokyo", "japan" ] }
{ _id: 2, results: [ "sydney", "australia" ] }




db.scores.find(
   { results: { $elemMatch: { $regex: *some regex* } } }
)

How do you convert this simple elemMatch example using spring mongodb data Query Criteria?

If the array contains object I can do it this way

Criteria criteria = 
   Criteria.where("results").
   elemMatch(
      Criteria.where("field").is("tokyo")
   );

But in my question, I dont have the "field"

Update:

I thought the Veeram's answer was going to work after trying it out

Criteria criteria = 
   Criteria.where("results").
   elemMatch(
      new Criteria().is("tokyo")
   );

It does not return anything. Am I missing something?

When i inspect the query object, it states the following:

Query: { "setOfKeys" : { "$elemMatch" : { }}}, Fields: null, Sort: null

On the other hand, If i modify the criteria using Criteria.where("field") like above,

Query: { "setOfKeys" : { "$elemMatch" : { "field" : "tokyo"}}}, Fields: null, Sort: null

I'm getting something but that's not how my data was structured, results is an array of strings not objects. I actually need to use regex, for simplicity , the above example is using .is

score 2 · Accepted Answer · answered Sep 11 '18 at 02:10

2

You can try below query.

Criteria criteria = Criteria.where("results").elemMatch(new Criteria().gte(80).lt(85));

answered Sep 11 '18 at 02:10

s7vr

73,656
11
106
127

cool looks like this would work. How is the performance of this kind of query i wonder. Can this be indexed? – user1955934 Sep 11 '18 at 02:13
Sure. You can index results. – s7vr Sep 11 '18 at 02:14
It doesn't seem to work as expected.. nothing gets returned – user1955934 Sep 13 '18 at 08:53
Looking more closely you don't need elemMatch for single query criteria. So `Criteria.where("results").is("tokyo")` should work for. Btw I'm not sure why is wont work on elemMatch while lt\gt works. – s7vr Sep 13 '18 at 12:54
You're right.. it's very unintuitive for me, i'm picturing elemMatch sort of like for loop... thx – user1955934 Sep 13 '18 at 15:02

score -1 · Answer 2 · answered Aug 12 '21 at 16:54

-1

Try this

Criteria criteria = Criteria.where("results").regex(".*tokyo.*","i");

answered Aug 12 '21 at 16:54

O.Ndiaye

1
1

2

Welcome to Stack Overflow, and thank you for contributing an answer. Would you kindly edit your answer to to include an explanation of your code? That will help future readers better understand what is going on, and especially those members of the community who are new to the language and struggling to understand the concepts. That's especially important when there's already an accepted answer that's been validated by the community. Under what conditions might your approach be preferred? Are you taking advantage of new capabilities? – Jeremy Caney Aug 13 '21 at 20:00

Spring MongoDB Data elemMatch Simple

2 Answers2