MongoDB: Is it possible to make a case-insensitive

Question

Example:

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

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

Answer 1

If you need to create the regexp from a variable, this is a much better way to do it: https://stackoverflow.com/a/10728069/309514

You can then do something like:

var string = "SomeStringToFind";
var regex = new RegExp(["^", string, "$"].join(""), "i");
// Creates a regex of: /^SomeStringToFind$/i
db.stuff.find( { foo: regex } );

This has the benefit be being more programmatic or you can get a performance boost by compiling it ahead of time if you're reusing it a lot.

Answer 2

One very important thing to keep in mind when using a Regex based query - When you are doing this for a login system, escape every single character you are searching for, and don't forget the ^ and $ operators. Lodash has a nice function for this, should you be using it already:

db.stuff.find({$regex: new RegExp(_.escapeRegExp(bar), $options: 'i'})

Why? Imagine a user entering .* as his username. That would match all usernames, enabling a login by just guessing any user's password.

Answer 3

I had faced a similar issue and this is what worked for me:

  const flavorExists = await Flavors.findOne({
    'flavor.name': { $regex: flavorName, $options: 'i' },
  });

Answer 4

TL;DR

Correct way to do this in mongo

Do not Use RegExp

Go natural And use mongodb's inbuilt indexing , search

Step 1 :

db.articles.insert(
   [
     { _id: 1, subject: "coffee", author: "xyz", views: 50 },
     { _id: 2, subject: "Coffee Shopping", author: "efg", views: 5 },
     { _id: 3, subject: "Baking a cake", author: "abc", views: 90  },
     { _id: 4, subject: "baking", author: "xyz", views: 100 },
     { _id: 5, subject: "Café Con Leche", author: "abc", views: 200 },
     { _id: 6, subject: "Сырники", author: "jkl", views: 80 },
     { _id: 7, subject: "coffee and cream", author: "efg", views: 10 },
     { _id: 8, subject: "Cafe con Leche", author: "xyz", views: 10 }
   ]
)

Step 2 :

Need to create index on whichever TEXT field you want to search , without indexing query will be extremely slow

db.articles.createIndex( { subject: "text" } )

step 3 :

db.articles.find( { $text: { $search: "coffee",$caseSensitive :true } } )  //FOR SENSITIVITY
db.articles.find( { $text: { $search: "coffee",$caseSensitive :false } } ) //FOR INSENSITIVITY

Answer 5

Using a filter works for me in C#.

string s = "searchTerm";
    var filter = Builders<Model>.Filter.Where(p => p.Title.ToLower().Contains(s.ToLower()));
                var listSorted = collection.Find(filter).ToList();
                var list = collection.Find(filter).ToList();

It may even use the index because I believe the methods are called after the return happens but I haven't tested this out yet.

This also avoids a problem of

var filter = Builders<Model>.Filter.Eq(p => p.Title.ToLower(), s.ToLower());

that mongodb will think p.Title.ToLower() is a property and won't map properly.