Practice Theoretical Questions

Common interview questions are listed below. For each question, take a moment to think before writing your answer. If you’d like, you can use AI to evaluate your response. Afterward, compare your answer with the provided model answer to understand how it can be improved.

Note: If you get confused and want to know the correct answer, write “Ed, give me the answer.”

Extra notes

• Schema-less means different documents in the same collection can have different fields.

• It is ideal for applications with changing or unstructured data.

Extra notes

• MongoDB often uses embedded documents instead of joins.

• It scales more easily horizontally.

Extra notes

• It supports extra data types like Date and ObjectId.

• It is more efficient for storage and querying than plain JSON.

Extra notes

• There is no enforced schema by default.

• It exists inside a database.

Extra notes

• It is like a row in a table, but it can contain nested data and arrays.

• Each document has a unique _id field.

Extra notes

• By default, _id is of type ObjectId, which encodes a timestamp and other unique values.

• We can set our own _id value, but it must be unique within the collection.

Extra notes

• The use keyword only switches the context; the database isn’t created until data is added.

• We can also explicitly create a collection with db.createCollection("myCollection").