MongoDB: Is it possible to make a case-insensitive query?

Question

Example:

> db.stuff.save({\"foo\":\"bar\"});

> db.stuff.find({\"foo\":\"bar\"}).count();
1
> db.stuff.find({\"foo\":\"BAR\"}).count();
0
         


        

Answer 1

The best method is in your language of choice, when creating a model wrapper for your objects, have your save() method iterate through a set of fields that you will be searching on that are also indexed; those set of fields should have lowercase counterparts that are then used for searching.

Every time the object is saved again, the lowercase properties are then checked and updated with any changes to the main properties. This will make it so you can search efficiently, but hide the extra work needed to update the lc fields each time.

The lower case fields could be a key:value object store or just the field name with a prefixed lc_. I use the second one to simplify querying (deep object querying can be confusing at times).

Note: you want to index the lc_ fields, not the main fields they are based off of.