Unique index in mongoDB 3.2 ignoring null values

Question

I want to add the unique index to a field ignoring null values in the unique indexed field and ignoring the documents that are filtered based on partialFilterExpression.

Answer 1

Yes, you can create partial index in MongoDB 3.2

Please see https://docs.mongodb.org/manual/core/index-partial/#index-type-partial

MongoDB recommend usage of partial index over sparse index. I'll suggest you to drop your sparse index in favor of partial index.