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. Updates all matching documents, not just the first, that match the selector.
db.cloneDatabase(fromhost)
Multi-updates
db.help([commandName]);
mongod

2. Returns help information for a command.
db.commandHelp("commandName")
$all
db.cloneDatabase(fromhost)
$pullAll

3. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$nin
$ne
undefined
object id

4. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$slice
$size
$gt

5. 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 ] } } }
Upsert
$lte
string
$addToSet

6. Command to get help docs on a specific command at the collection level.
$inc
Cursor
regular expression
db.<col>.help([commandName]);

7. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
64-Bit Integer
$gte
show collections
boolean

8. ...
$mod
db.commandHelp("commandName")
embedded document
batch insert

9. Operator allowing the partial specification of fields in an embedded document in an array.
$elemMatch
$rename
document
use <database name>

10. changes the database on which you are working.
db.<collection>.insert({document});
$pullAll
use <database name>
$nin

11. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
$lt
$push
$not
binary data

12. Binary-encoded serialization of mongo documents.
BSON
$mod
db.<collection>.insert({document});
Object.bsonsize({document});

13. 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.
help
batch insert
Update Modifiers
$gt

14. Javascript code. Documents can contain code as values.
date
mongod
db.cloneDatabase(fromhost)
code

15. Data structure used to store all other data in mongo databases.
$where
document
db.<collection>.find([properties]);
$pushAll

16. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$gt
object id
db.<collection>.insert({document});
$slice

17. Standard javascript regular expressions. These can be stored in documents
regular expression
$in
Cursor
mongod

18. Returns all the documents matching the optional properties.
$addToSet
db.<collection>.find([properties]);
db.commandHelp("commandName")
$where

19. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
undefined
$in
$pullAll
$gte

20. set of UTF-8 characters.
db.<col>.update({selector},{document});
$
$ne
string

21. command to start the mongo shell.
db.cloneDatabase(fromhost)
mongo
db.cloneDatabase(fromhost)
string

22. Deletes a given field. ex: { $unset : { field : 1} }
$size
db.commandHelp("commandName")
$unset
regular expression

23. Operator allowing the execution of arbitrary javascript as part of the selector.
string
$pullAll
$rename
$where

24. Returns the size of a document after it is converted to BSON from the JSON-like original.
Object.bsonsize({document});
object id
$or
$not

25. changes the database on which you are working.
$lt
db.<col>.remove({selector});
use <database name>
$push

26. String of arbitrary bytes.
key.index
Upsert
binary data
use <database name>

27. In BSON - represents the smallest possible value.
minimum value
32-Bit Integer
$not
Update Modifiers

28. Set or list of values.
db.<collection>.find([properties]);
db.<collection>.find([properties]);
array
document

29. Adds a document to a collection.
db.<collection>.insert({document});
string
mongod
$nin

30. Returns one document matching the optional properties.
db.<collection>.insert({document});
mongod
db.<collection>.findOne([properties]);
code

31. command to start the mongodb process.
mongod
$addToSet
Update Modifiers
$or

32. Deletes documents from the collection based on the selector.
Cursor
db.runCommand({fsync:1,lock:1,async:1})
$mod
db.<col>.remove({selector});

33. Contains query conditional used to check if a value contains the field value.
db.cloneDatabase(fromhost)
$pushAll
maximum value
$in

34. Deletes documents from the collection based on the selector.
Multi-updates
db.<col>.remove({selector});
$not
db.<collection>.insert({document});

35. A document contained by a parent document. The embedded document is a value of a key in the parent document.
$pullAll
embedded document
db.<col>.help([commandName]);
$not

36. Syntax used for selectors to be specific to a certain element position within an array.
Upsert
$nin
db.myCollection.ensureIndex({keypattern},[{options}])
key.index

37. Command to get help docs on a specific command at the db level.
document
db.help([commandName]);
$addToSet
$rename

38. 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.
$or
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
date
$pullAll

39. Used to describe a variable as not having been initialized.
$push
$ne
undefined
object id

40. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
regular expression
$pull
$slice
$inc

41. 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"}});
undefined
$set
mongo
$elemMatch

42. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$inc
db.myCollection.ensureIndex({keypattern},[{options}])
db.getLastError()
db.<col>.help([commandName]);

43. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
Cursor
db.cloneDatabase(fromhost)
null
binary data

44. Unique 12-byte ID for documents.
db.commandHelp("commandName")
object id
db.commandHelp("commandName")
$ne

45. 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 } }
use <database name>
$gt
$push
Cursor

46. 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
64-bit floating point numbers
$pullAll
32-Bit Integer

47. 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})
db.myCollection.ensureIndex({keypattern},[{options}])
64-Bit Integer
null

48. 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.<collection>.findOne([properties]);
Upsert
embedded document
$inc

49. Lists all the collections in the database in use.
32-Bit Integer
show collections
$addToSet
64-Bit Integer

50. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
64-Bit Integer
Object.bsonsize({document});
document
db.getLastError()