Test your basic knowledge |

Mongo Db

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Command to get help docs on a specific command at the collection level.
Upsert
db.<col>.help([commandName]);
date
embedded document

2. Deletes a given field. ex: { $unset : { field : 1} }
binary data
$unset
$or
minimum value

3. Adds a document to a collection.
db.<collection>.insert({document});
mongod
$gte
Update Modifiers

4. changes the database on which you are working.
db.<collection>.find([properties]);
use <database name>
db.<col>.help([commandName]);
$in

5. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
null
db.commandHelp("commandName")
db.<col>.remove({selector});

6. command to start the mongo shell.
db.getLastError()
$addToSet
mongo
binary data

7. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$mod
db.<collection>.insert({document});
$or
$nin

8. Array specific conditional used to select based on the length or set-size of an array field value.
Multi-updates
$size
$slice
$addToSet

9. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
string
32-Bit Integer
code

10. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$ne
mongod
$mod
$or

11. Operator allowing the execution of arbitrary javascript as part of the selector.
$pop
minimum value
$where
db.<col>.remove({selector});

12. Update a document in the collection.
maximum value
Object.bsonsize({document});
db.<col>.update({selector},{document});
array

13. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$nin
$pullAll
mongo
db.commandHelp("commandName")

14. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
Cursor
show collections
$addToSet
db.<col>.remove({selector});

15. In BSON - represents the smallest possible value.
db.cloneDatabase(fromhost)
document
Update Modifiers
minimum value

16. Operator allowing the partial specification of fields in an embedded document in an array.
$not
db.cloneDatabase(fromhost)
$lte
$elemMatch

17. Used to describe a variable as not having been initialized.
db.<col>.remove({selector});
$pull
$set
undefined

18. command to start the mongodb process.
mongod
help
key.index
$push

19. set of UTF-8 characters.
$where
string
db.runCommand({fsync:1,lock:1,async:1})
array

20. Copies an entire database from one name on one server to another name on another server. Omit frmHostName to copy from one name to another on the same server.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
mongo
db.<col>.remove({selector});
mongod

21. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
mongod
db.<col>.remove({selector});
$slice
$set

22. Meta query conditional used to negate the selector.
$nin
$not
minimum value
Cursor

23. Javascript code. Documents can contain code as values.
$size
code
db.<collection>.insert({document});
embedded document

24. Update call that inserts a new document if no update match is found. Allows the same code to be used for inserts as well as updates.
db.myCollection.ensureIndex({keypattern},[{options}])
Upsert
$addToSet
$pop

25. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
$rename
$gt
64-bit floating point numbers
object id

26. ...
$size
$where
batch insert
$nin

27. Clone the current database (implied by 'db') from another host.
db.getLastError()
db.cloneDatabase(fromhost)
mongo
db.<col>.update({selector},{document});

28. Command to get help docs on a specific command at the db level.
mongod
Upsert
$gte
db.help([commandName]);

29. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
$push
$elemMatch
db.<col>.help([commandName]);

30. command to start the mongo shell.
mongo
Multi-updates
maximum value
32-Bit Integer

31. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
Upsert
$gte
Multi-updates
batch insert

32. Update modifier that set the value of a key and if the key does not exist, it will create the key. ex: db.<col>.update({selector},{"$set":{"someKey":"someValue"}});
$set
use <database name>
$rename
$lte

33. Returns one document matching the optional properties.
$unset
$size
Update Modifiers
db.<collection>.findOne([properties]);

34. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$gte
32-Bit Integer
db.myCollection.ensureIndex({keypattern},[{options}])
$or

35. Set or list of values.
db.<collection>.find([properties]);
array
use <database name>
Update Modifiers

36. The standard number representation in the javascript shell.
Cursor
64-bit floating point numbers
db.getLastError()
db.cloneDatabase(fromhost)

37. Returns all the documents matching the optional properties.
boolean
64-bit floating point numbers
db.<collection>.find([properties]);
$gt

38. Binary-encoded serialization of mongo documents.
db.help([commandName]);
code
BSON
db.<col>.remove({selector});

39. A document contained by a parent document. The embedded document is a value of a key in the parent document.
$addToSet
date
Cursor
embedded document

40. In BSON - represents the largest possible value.
$addToSet
use <database name>
boolean
maximum value

41. Lists all the collections in the database in use.
Cursor
$nin
db.<collection>.insert({document});
show collections

42. Array specific conditional allowing matching on multiple elements within an array. The operation is non strict on the sequence of the values in the passed selector array.
$
db.<collection>.find([properties]);
$all
db.<col>.update({selector},{document});

43. Adds a value to the array only if its not in the array already. Otherwise, if the field is not present, it sets the field to the array value. ex: { $addToSet : { a : { $each : [ 3 , 5 , 6 ] } } }
$addToSet
$in
db.<collection>.insert({document});
$gt

44. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
mongo
key.index
code
$gt

45. Flushes all pending writes to data files. The lock option allows one to safely snapshot the database's data files. The async option returns focus to the console immediately while the task runs in the background.
db.runCommand({fsync:1,lock:1,async:1})
array
db.<col>.help([commandName]);
null

46. Removes an element from an array based on the value of the field option being 1 or -1 for last or first element respectively. ex: { $pop : { field : -1 } }
db.<collection>.find([properties]);
db.<collection>.find([properties]);
$pop
db.myCollection.ensureIndex({keypattern},[{options}])

47. String of arbitrary bytes.
use <database name>
$elemMatch
boolean
binary data

48. Meta query conditional generating a modulus with the selector operand. Checks to see if the field value when divided by one value has the remainder of the second value.
$mod
$where
db.cloneDatabase(fromhost)
mongod

49. Clone the current database (implied by 'db') from another host.
null
db.cloneDatabase(fromhost)
64-Bit Integer
embedded document

50. Stored as milliseconds since the epoch.
db.<collection>.find([properties]);
date
db.<collection>.insert({document});
64-Bit Integer