How do we explicitly define data types for a MongoDB collection

MongoDB provides the capability to validate documents during updates and insertions. Validation rules are specified on a per-collection basis using the validator option, which takes a document that specifies the validation rules or expressions. Specify the expressions using any query operators, with the exception of$near, $nearSphere, $text, and $where.

Add document validation to an existing collection using the collMod command with the validator option. You can also specify document validation rules when creating a new collection usingdb.createCollection() with the validator option, as in the following:

db.createCollection( "contacts",
   { validator: { $or:
      [
         { phone: { $type: "string" } },
         { email: { $regex: /@mongodb\.com$/ } },
         { status: { $in: [ "Unknown", "Incomplete" ] } }
      ]
   }
} )