MCQs Of Day 19: MongoDB Data Import and Export

1. Which command is used to import data into MongoDB?

A) mongoimport
B) mongoexport
C) mongodump
D) mongorestore

Answer: A) mongoimport
Explanation: The mongoimport command is used to import data into MongoDB from various file formats like JSON, CSV, or TSV.

2. What is the default file format for `mongoimport`?

A) CSV
B) JSON
C) BSON
D) XML

Answer: B) JSON
Explanation: The default file format for mongoimport is JSON. If no type is specified, it assumes the file is in JSON format.

3. Which flag is used in `mongoimport` to specify that the input data is in CSV format?

A) --type csv
B) --csv
C) --input-type csv
D) --csv-file

Answer: A) --type csv
Explanation: The --type csv flag is used to indicate that the input data is in CSV format.

4. Which option in `mongoimport` allows you to skip the first line of a CSV file, which contains the header?

A) --headerline
B) --noheader
C) --skipheader
D) --ignoreheader

Answer: A) --headerline
Explanation: The --headerline option tells mongoimport to use the first row of the CSV file as field names (headers).

5. What does the `--jsonArray` option do in the `mongoimport` command?

A) Treats the JSON file as a single document
B) Treats the JSON file as an array of documents
C) Ignored in the import process
D) Converts JSON data to CSV format

Answer: B) Treats the JSON file as an array of documents
Explanation: The --jsonArray option tells MongoDB to treat the entire JSON file as an array of documents, where each element in the array is a separate document.

6. Which command is used to export data from MongoDB?

A) mongoimport
B) mongoexport
C) mongodump
D) mongorestore

Answer: B) mongoexport
Explanation: The mongoexport command is used to export data from MongoDB to a file in formats like JSON, CSV, or TSV.

7. What is the default format for `mongoexport`?

A) CSV
B) JSON
C) BSON
D) TSV

Answer: B) JSON
Explanation: The default format for mongoexport is JSON, unless another format is specified.

8. How can you specify the fields to be exported in `mongoexport`?

A) --fields
B) --export-fields
C) --output-fields
D) --select-fields

Answer: A) --fields
Explanation: The --fields option in mongoexport allows you to specify which fields to include in the exported data.

9. Which command is used to export data to BSON format?

A) mongoimport
B) mongoexport
C) mongodump
D) mongorestore

Answer: B) mongoexport
Explanation: The mongoexport command can export data to BSON format using the --type bson option.

10. Which MongoDB command allows you to perform a full backup of your database?

A) mongoimport
B) mongoexport
C) mongodump
D) mongorestore

Answer: C) mongodump
Explanation: The mongodump command is used to perform a full backup of your MongoDB database, exporting the data in BSON format.

11. Which of the following options can be used to filter documents during export in `mongoexport`?

A) --query
B) --filter
C) --select
D) --condition

Answer: A) --query
Explanation: The --query option allows you to filter documents during export by specifying a query in JSON format.

12. How can you specify a custom delimiter when importing a CSV file into MongoDB?

A) --delimiter
B) --delim
C) --csv-delim
D) --custom-delimiter

Answer: B) --delim
Explanation: The --delim option specifies a custom delimiter (e.g., | or ;) for CSV files when importing data.

13. Which command is used to restore data from a BSON file?

A) mongoimport
B) mongoexport
C) mongodump
D) mongorestore

Answer: D) mongorestore
Explanation: The mongorestore command is used to restore data from a BSON file that was previously backed up using mongodump.

14. What happens if you run `mongoimport` with the `--upsert` option?

A) It creates new documents only.
B) It updates existing documents or inserts new ones.
C) It skips existing documents.
D) It overwrites all existing documents.

Answer: B) It updates existing documents or inserts new ones.
Explanation: The --upsert option allows MongoDB to either update existing documents (based on the _id) or insert new ones if they don't already exist.

15. Which of the following commands will export the `products` collection to a CSV file named `products.csv`?

A) mongoexport --db shop --collection products --out products.csv --type csv
B) mongoimport --db shop --collection products --out products.csv --type csv
C) mongoexport --db shop --collection products --file products.csv --type csv
D) mongoexport --db shop --collection products --out products.csv --format csv

Answer: C) mongoexport --db shop --collection products --file products.csv --type csv
Explanation: The correct command to export data from MongoDB to a CSV file is mongoexport --file.

16. Which of the following is true about BSON format?

A) It is a binary format used by MongoDB for data storage.
B) It is human-readable.
C) It is a text-based format.
D) It is used exclusively for data import.

Answer: A) It is a binary format used by MongoDB for data storage.
Explanation: BSON (Binary JSON) is a binary format that MongoDB uses internally for data storage.

17. How can you specify the database when using `mongoimport`?

A) --db
B) --database
C) --dbname
D) --db-name

Answer: A) --db
Explanation: The --db option is used in mongoimport to specify the database where the data should be imported.

18. What will happen if you try to import a CSV file without the `--headerline` option?

A) It will fail with an error.
B) The first row will be used as data, not field names.
C) The import will succeed, but no fields will be defined.
D) It will automatically create field names.

Answer: B) The first row will be used as data, not field names.
Explanation: Without the --headerline option, MongoDB treats the first row of a CSV file as data rather than as headers.

19. What is the correct option to specify the output file when using `mongoexport`?

A) --file
B) --out
C) --output
D) --destination

Answer: B) --out
Explanation: The --out option is used to specify the output file where the data should be exported.

20. In which format does `mongoexport` export the data by default?

A) BSON
B) CSV
C) JSON
D) TSV

Answer: C) JSON
Explanation: The default export format for mongoexport is JSON.

21. How can you exclude a specific field during export in `mongoexport`?

A) --exclude
B) --omit
C) --fields
D) --projection

Answer: D) --projection
Explanation: The --projection option allows you to exclude specific fields from being exported by specifying a projection document.

22. What is the purpose of `--type` flag in `mongoimport` and `mongoexport`?

A) To specify the file format
B) To specify the type of data being exported
C) To specify the database type
D) To specify the field type

Answer: A) To specify the file format
Explanation: The --type flag is used to specify the file format (e.g., json, csv, tsv) for both mongoimport and mongoexport.

23. Which command is used to view the data after importing it into MongoDB?

A) mongoimport --view
B) mongoexport --view
C) db.collection.find()
D) mongodump --view

Answer: C) db.collection.find()
Explanation: To view data in MongoDB after importing, you use the db.collection.find() command.

24. Which of the following can be used to import data into an existing MongoDB collection?

A) mongoimport
B) mongoimport --upsert
C) mongoimport --insert
D) mongoimport --overwrite

Answer: B) mongoimport --upsert
Explanation: The --upsert option allows you to insert new documents or update existing ones in the collection.

25. How would you export data in tab-separated values (TSV) format?

A) --type tsv
B) --tsv
C) --output tsv
D) --format tsv

Answer: A) --type tsv
Explanation: The --type tsv flag is used to specify that the data should be exported in TSV format.

26. Which of the following commands exports the `users` collection from the `test` database into a JSON file?

A) mongoexport --db test --collection users --out users.json
B) mongoimport --db test --collection users --out users.json
C) mongoexport --db test --collection users --file users.json
D) mongoexport --db test --collection users --type json --out users.json

Answer: A) mongoexport --db test --collection users --out users.json
Explanation: The correct syntax for exporting data from MongoDB into a JSON file is option A.

27. How can you ensure that `mongoimport` adds data to a specific collection?

A) Use the --collection flag
B) Use the --type flag
C) Use the --upsert flag
D) Use the --db flag

Answer: A) Use the --collection flag
Explanation: The --collection option specifies which collection the data will be imported into.

28. What type of data is BSON designed to store?

A) Textual data
B) Binary data
C) JSON-like data
D) CSV data

Answer: C) JSON-like data
Explanation: BSON is a binary representation of JSON-like documents, which supports additional data types that JSON cannot.

29. Which command is used to import data into a specific MongoDB database?

A) mongoimport --db
B) mongoimport --database
C) mongoimport --dbname
D) mongoimport --collection

Answer: A) mongoimport --db
Explanation: The --db option is used to specify the database into which the data will be imported.

30. What does the `--drop` flag do in the `mongoimport` command?

A) Drops the database before importing
B) Drops the collection before importing data
C) Drops the field from the collection
D) Drops the document after importing

Answer: B) Drops the collection before importing data
Explanation: The --drop flag removes the existing collection before importing new data, ensuring that the collection is fresh.

31. In the `mongoimport` command, what does the `--fields` option do?

A) Specifies the order of fields to be imported
B) Specifies which fields to export
C) Specifies the field names for mapping CSV/JSON columns
D) Specifies which database to import the fields into

Answer: C) Specifies the field names for mapping CSV/JSON columns
Explanation: The --fields option allows you to map CSV or JSON columns to the corresponding field names in MongoDB.

32. What does the `--upsert` option do in `mongoimport`?

A) Inserts only new documents
B) Updates existing documents or inserts new ones
C) Deletes existing documents before import
D) Imports data without any validation

Answer: B) Updates existing documents or inserts new ones
Explanation: The --upsert option allows MongoDB to update existing documents based on _id or insert new ones if no matching document is found.

33. What happens if you run `mongoexport` with no query filter?

A) All documents in the collection will be exported
B) No data will be exported
C) Only indexed documents will be exported
D) Only the first document will be exported

Answer: A) All documents in the collection will be exported
Explanation: If no query filter is specified, mongoexport exports all documents in the collection.

34. What is the default field delimiter for `mongoimport` when importing CSV data?

A) Space
B) Comma
C) Tab
D) Semicolon

Answer: B) Comma
Explanation: By default, mongoimport assumes that CSV data is comma-separated.

35. What is the maximum number of fields allowed in a single document when importing CSV using `mongoimport`?

A) 100 fields
B) 200 fields
C) 500 fields
D) Unlimited fields

Answer: D) Unlimited fields
Explanation: MongoDB does not impose a strict limit on the number of fields in a document, but performance can degrade with very large documents.

36. Which format does `mongoexport` support for exporting data?

A) BSON
B) XML
C) CSV
D) JSON

Answer: C) CSV
Explanation: mongoexport supports exporting data in JSON, CSV, and TSV formats.

37. What happens if you use `mongoexport` with the `--jsonArray` flag?

A) The data will be exported as an array of JSON objects
B) The data will be exported as a single JSON object
C) The data will be exported in BSON format
D) The data will be skipped

Answer: A) The data will be exported as an array of JSON objects
Explanation: The --jsonArray flag treats the JSON data as an array of documents during export.

38. Which option allows `mongoexport` to exclude the `_id` field from the exported data?

A) --excludeId
B) --omitId
C) --noId
D) --projection {_id: 0}

Answer: D) --projection {_id: 0}
Explanation: The --projection option allows you to exclude specific fields, including _id, by setting it to 0.

39. Which of the following statements about `mongoimport` and `mongoexport` is true?

A) Both commands are used for importing and exporting BSON data only
B) Both commands support JSON, CSV, and TSV formats
C) Both commands support BSON only for imports
D) Both commands are limited to importing and exporting from the same database

Answer: B) Both commands support JSON, CSV, and TSV formats
Explanation: mongoimport and mongoexport can handle JSON, CSV, and TSV file formats for data import and export.

40. How can you import data into a specific MongoDB collection?

A) By using the --database option
B) By using the --collection option
C) By using the --db option
D) By using the --data option

Answer: B) By using the --collection option
Explanation: The --collection option is used to specify the target collection when importing data into MongoDB.

41. What happens if you run `mongoimport` with the `--drop` option?

A) It overwrites the collection
B) It drops the database
C) It drops the collection before importing data
D) It ignores existing documents

Answer: C) It drops the collection before importing data
Explanation: The --drop flag removes the existing collection before importing new data.

42. What happens if the input file for `mongoimport` is in the wrong format?

A) The import will fail with an error message
B) The import will continue without any errors
C) The import will skip the invalid rows
D) The data will be inserted in the wrong format

Answer: A) The import will fail with an error message
Explanation: If the input file is in the wrong format, mongoimport will fail and display an error message.

43. How can you include or exclude specific fields in `mongoexport`?

A) By using the --include flag
B) By using the --fields flag
C) By using the --projection flag
D) By using the --filter flag

Answer: C) By using the --projection flag
Explanation: The --projection flag allows you to include or exclude specific fields during export by specifying them in the query.

44. Which of the following is true about BSON format?

A) BSON is a binary version of CSV format
B) BSON is a binary representation of JSON
C) BSON is a text-based data format like CSV
D) BSON is not used in MongoDB

Answer: B) BSON is a binary representation of JSON
Explanation: BSON (Binary JSON) is a binary representation of JSON-like documents used in MongoDB to store data.

45. Which of the following is a correct syntax for exporting data in CSV format using `mongoexport`?

A) mongoexport --db test --collection users --type csv --out users.csv
B) mongoexport --db test --collection users --type csv --file users.csv
C) mongoexport --db test --collection users --csv --out users.csv
D) mongoexport --db test --collection users --out users.csv --format csv

Answer: A) mongoexport --db test --collection users --type csv --out users.csv
Explanation: The correct syntax to export data in CSV format is option A.

46. What is the default behavior of `mongoimport` if no specific import options are provided?

A) It will ignore duplicate documents
B) It will drop the collection before importing data
C) It will overwrite existing data
D) It will insert data without validation

Answer: A) It will ignore duplicate documents
Explanation: By default, mongoimport will not overwrite or upsert documents; it simply inserts new documents without validation for duplicates.

47. How do you specify a query filter in the `mongoexport` command to export specific documents?

A) --query
B) --filter
C) --condition
D) --where

Answer: A) --query
Explanation: The --query option is used to specify a filter when exporting specific documents from MongoDB.

48. Which of the following is used to export data from MongoDB in TSV format?

A) --type tsv
B) --format tsv
C) --output tsv
D) --tsv

Answer: A) --type tsv
Explanation: The --type tsv option is used to export data in TSV format using mongoexport.

49. How would you export data with specific fields from a collection using `mongoexport`?

A) Use the --fields option
B) Use the --project option
C) Use the --query option
D) Use the --select option

Answer: A) Use the --fields option
Explanation: The --fields option specifies which fields to include when exporting data from MongoDB.

50. Which command is used to import data from a CSV file into MongoDB?

A) mongoimport --type csv --file data.csv
B) mongoimport --db test --collection users --file data.csv
C) mongoimport --csv --file data.csv
D) mongoimport --csv --type json --file data.csv

Answer: B) mongoimport --db test --collection users --file data.csv
Explanation: The mongoimport command with the correct options allows importing data from a CSV file into the specified database and collection.

MCQs Of Day 19: MongoDB Data Import and Export