Question from the MongoDB test

A unique index ensures that no duplicate values are allowed in the indexed field, while a composite index allows an index to be created across multiple fields, but does not ensure uniqueness.

A unique index creates a primary key for the collection, while a composite index cannot be used as a primary key.

A single index speeds up search queries, while a composite index is mainly used for sorting documents.

A unique index is automatically created for the _id field, while a composite index must be created manually.