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. A document contained by a parent document. The embedded document is a value of a key in the parent document.
code
embedded document
mongo
$not

2. changes the database on which you are working.
$or
$all
use <database name>
show collections

3. Lists all the collections in the database in use.
$nin
$size
show collections
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

4. Set or list of values.
db.cloneDatabase(fromhost)
array
Object.bsonsize({document});
Multi-updates

5. set of UTF-8 characters.
string
$rename
$pushAll
mongod

6. 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 } }
$inc
$push
mongo
db.<collection>.find([properties]);

7. Syntax used for selectors to be specific to a certain element position within an array.
array
$pull
mongo
key.index

8. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
mongod
32-Bit Integer
db.<collection>.find([properties]);
undefined

9. 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.
$lt
$mod
64-bit floating point numbers
$pull

10. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
help
$all
object id

11. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$rename
$in
$slice
$ne

12. 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.
Upsert
code
$gte
$mod

13. Command to get help docs on a specific command at the collection level.
code
mongo
db.<col>.help([commandName]);
$unset

14. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
db.commandHelp("commandName")
object id
Multi-updates
$lt

15. 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.
$ne
$pushAll
show collections
db.runCommand({fsync:1,lock:1,async:1})

16. Binary-encoded serialization of mongo documents.
$or
$lte
db.myCollection.ensureIndex({keypattern},[{options}])
BSON

17. Query conditional allowing the selector to choose between more than one optional criteria.
$or
binary data
db.help([commandName]);
64-Bit Integer

18. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
$rename
$
$where

19. Javascript code. Documents can contain code as values.
code
$in
64-bit floating point numbers
$pop

20. The standard number representation in the javascript shell.
db.myCollection.ensureIndex({keypattern},[{options}])
64-bit floating point numbers
use <database name>
boolean

21. Returns help information for a command.
db.<collection>.findOne([properties]);
$all
db.getLastError()
db.commandHelp("commandName")

22. Unique 12-byte ID for documents.
$push
32-Bit Integer
object id
key.index

23. 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"}});
$in
db.<col>.remove({selector});
$set
$

24. Adds a document to a collection.
db.<collection>.insert({document});
db.<collection>.findOne([properties]);
date
regular expression

25. Meta query conditional used to negate the selector.
$push
db.<col>.remove({selector});
$not
Update Modifiers

26. Operator allowing the partial specification of fields in an embedded document in an array.
$or
mongo
db.myCollection.ensureIndex({keypattern},[{options}])
$elemMatch

27. Used to represent both a null value and a nonexistent field.
db.<col>.update({selector},{document});
null
$size
db.cloneDatabase(fromhost)

28. 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 } }
$pushAll
$all
use <database name>
show collections

29. 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]);
mongod
Upsert
$

30. 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.
$rename
$all
$nin
maximum value

31. Stored as milliseconds since the epoch.
boolean
$all
db.runCommand({fsync:1,lock:1,async:1})
date

32. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
array
64-Bit Integer
db.<collection>.find([properties]);
Upsert

33. In BSON - represents the smallest possible value.
db.<col>.remove({selector});
$lte
minimum value
Cursor

34. Standard javascript regular expressions. These can be stored in documents
$or
$where
db.<collection>.find([properties]);
regular expression

35. Command to list commands and descriptions of those commands in the context of the database.
$push
help
db.<col>.help([commandName]);
binary data

36. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
document
help
db.<collection>.find([properties]);
$gte

37. command to start the mongo shell.
64-bit floating point numbers
$where
binary data
mongo

38. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
document
db.commandHelp("commandName")
$nin
code

39. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
db.commandHelp("commandName")
$nin
$gt
$rename

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.
object id
Update Modifiers
regular expression
mongo

41. changes the database on which you are working.
db.<col>.update({selector},{document});
show collections
$size
use <database name>

42. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.getLastError()
boolean
$slice
db.cloneDatabase(fromhost)

43. In BSON - represents the largest possible value.
maximum value
64-bit floating point numbers
Multi-updates
db.commandHelp("commandName")

44. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pull
object id
$ne
$all

45. Standard binary data type.
$pull
boolean
$gt
$where

46. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
key.index
code
Cursor
db.myCollection.ensureIndex({keypattern},[{options}])

47. Update a document in the collection.
object id
$addToSet
use <database name>
db.<col>.update({selector},{document});

48. Updates all matching documents, not just the first, that match the selector.
Multi-updates
mongo
$gte
db.<col>.remove({selector});

49. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
64-Bit Integer
$unset
$elemMatch
$slice

50. 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 },
$
array
regular expression
boolean