Case insensitive search in Mongo

Question

I am using a case insensitive search in Mongo, something similar to https://stackoverflow.com/q/5500823/1028488.

ie I am using a regex with options i. But I am am ha

Answer 1

UPDATE: As of MongoDB 2.4 one would use a "text" index and full text search query to do this. You can read about them here. If using a recent MongoDB the approach below would be silly and unecessary.

However, if you have MongoDB < 2.4.0 you could use a regular expression like so:

> db.reg.insert({searchword: "win"})
> db.reg.insert({searchword: "window"})
> db.reg.insert({searchword: "Win"})

> db.reg.find()
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e36dd68c9021e453d13"), "searchword" : "window" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

> db.reg.find({ searchword: /^win$/i })
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

However, your version wasn't working because you don't need the "/"s when using the $regex operator:

> db.reg.find({ searchword: { $regex: "^win$", $options: '-i' }})
{ "_id" : ObjectId("4ecd2e33dd68c9021e453d12"), "searchword" : "win" }
{ "_id" : ObjectId("4ecd2e39dd68c9021e453d14"), "searchword" : "Win" }

Please note that case insensitive queries do not use the index so it might make sense to make a lowercase searchword field so that you can speed that query up.

Go here for more info on RegularExpressions