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.
$addToSet
$size
db.<col>.help([commandName]);
show collections

2. set of UTF-8 characters.
$pushAll
db.<col>.remove({selector});
embedded document
string

3. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
db.cloneDatabase(fromhost)
$lte
embedded document
Upsert

4. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.<col>.help([commandName]);
date
$gte
db.getLastError()

5. Array specific conditional used to select based on the length or set-size of an array field value.
$size
mongo
Upsert
db.<col>.remove({selector});

6. Contains query conditional used to check if a value contains the field value.
$slice
$pushAll
$in
db.commandHelp("commandName")

7. command to start the mongodb process.
mongod
db.<col>.remove({selector});
db.<collection>.find([properties]);
undefined

8. A document contained by a parent document. The embedded document is a value of a key in the parent document.
db.getLastError()
db.commandHelp("commandName")
embedded document
use <database name>

9. Meta query conditional used to negate the selector.
$gte
mongod
$nin
$not

10. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
document
$inc
null
db.<col>.update({selector},{document});

11. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
32-Bit Integer
db.<collection>.findOne([properties]);
object id
$nin

12. Syntax used for selectors to be specific to a certain element position within an array.
$inc
key.index
$gt
$unset

13. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.cloneDatabase(fromhost)
db.<collection>.find([properties]);
Update Modifiers
$gte

14. In BSON - represents the smallest possible value.
document
Update Modifiers
minimum value
mongo

15. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
db.<collection>.find([properties]);
string
$all
$lt

16. ...
$where
db.<collection>.find([properties]);
db.cloneDatabase(fromhost)
batch insert

17. Clone the current database (implied by 'db') from another host.
$not
db.cloneDatabase(fromhost)
$ne
array

18. Standard binary data type.
boolean
$size
$ne
db.<collection>.insert({document});

19. command to start the mongo shell.
$slice
mongo
Object.bsonsize({document});
BSON

20. 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 } }
use <database name>
$pop
$slice
32-Bit Integer

21. command to start the mongo shell.
mongo
db.<collection>.insert({document});
$nin
help

22. 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"}});
db.<col>.remove({selector});
$slice
$set
minimum value

23. Appends a value to field - if the field is an existing array. Otherwise it sets the field to the array [value] if field is not present. ex: { $push : { field : value } }
$all
$push
$addToSet
$size

24. Returns help information for a command.
64-bit floating point numbers
$pullAll
$push
db.commandHelp("commandName")

25. Unique 12-byte ID for documents.
help
string
$rename
object id

26. Returns all the documents matching the optional properties.
minimum value
Upsert
help
db.<collection>.find([properties]);

27. 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.
$addToSet
minimum value
$where
db.runCommand({fsync:1,lock:1,async:1})

28. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
db.commandHelp("commandName")
$pop
db.<col>.remove({selector});
$pullAll

29. Lists all the collections in the database in use.
show collections
db.getLastError()
$pull
$gt

30. Set or list of values.
$not
array
regular expression
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

31. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pullAll
$pull
$in
db.cloneDatabase(fromhost)

32. 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.
use <database name>
$mod
BSON
regular expression

33. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
db.<col>.help([commandName]);
string
Upsert
$ne

34. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$rename
$pull
$gt
db.cloneDatabase(fromhost)

35. 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.
BSON
db.<collection>.find([properties]);
Upsert
document

36. Update a document in the collection.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
boolean
db.<collection>.insert({document});
db.<col>.update({selector},{document});

37. String of arbitrary bytes.
binary data
$lt
$ne
db.help([commandName]);

38. Operator allowing the execution of arbitrary javascript as part of the selector.
$or
$where
db.<collection>.findOne([properties]);
db.<collection>.insert({document});

39. Updates all matching documents, not just the first, that match the selector.
Multi-updates
object id
Object.bsonsize({document});
db.<collection>.find([properties]);

40. Special keys passed in an update call to specify complex update operations - such as alter - adding - or removing keys - and even manipulating arrays and embedded documents.
db.cloneDatabase(fromhost)
$
$lt
Update Modifiers

41. Adds a document to a collection.
db.<collection>.insert({document});
use <database name>
date
BSON

42. changes the database on which you are working.
binary data
$mod
use <database name>
code

43. Deletes documents from the collection based on the selector.
$gte
embedded document
db.commandHelp("commandName")
db.<col>.remove({selector});

44. Clone the current database (implied by 'db') from another host.
db.commandHelp("commandName")
db.cloneDatabase(fromhost)
undefined
$size

45. Stored as milliseconds since the epoch.
use <database name>
undefined
mongo
date

46. Appends each value in the value_array to the field - if field is an existing array. Otherwise - it sets the field to the array value_array - if field is not present ex: { $pushAll : { field : value_array } }
64-bit floating point numbers
$pushAll
mongod
$unset

47. Returns one document matching the optional properties.
32-Bit Integer
$set
undefined
db.<collection>.findOne([properties]);

48. Returns all the documents matching the optional properties.
mongo
db.<col>.help([commandName]);
db.<collection>.find([properties]);
db.cloneDatabase(fromhost)

49. Positional operator that holds the position of the first matched array item in the query. Used to find an array member and then manipulate it. ex: {$inc:{'comments.$.votes':1}} where comments looks like: "comments" : [ { "by" : "joe", "votes" : 3 },
$
db.<collection>.insert({document});
db.<collection>.find([properties]);
$gte

50. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
undefined
$rename
document
64-Bit Integer