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I have a mongodb collection like 


{
    template_id: { type: String, required: true },
    owner: {
        user_id: { type: String, required: true }
    },
    assignee: {
        user_id: { type: String, required: false }
    }
    //...other fields
}

There is a compound index (non-sparse & non-unique) for this document,

{ template_id: 1, owner: 1, assignee: 1 }

In this document the assignee may have value or may be null. However, the query pattern for fetching records having null is important.

Are records having null values indexed so that I can use for querying based in them?

Sharath Chandra
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  • *"In this document the owner and assignee may have value or may be null"* - Then your schema is incorrect since `required` means it cannot be either missing or `null`. There are also specific differences between "missing" and `null` for both queries and indexes. – Neil Lunn Apr 08 '19 at 11:20
  • I have updated the schema. The business scenario is field "assignee" may or may not be available during the save operation. If its not available, then the field "assignee" will be saved with null value. The query for all unassigned records then would be : "fetch all records where assignee is null". In this case does the compound index work or will it go for a full scan ? – Sharath Chandra Apr 08 '19 at 16:13

0 Answers0