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. Lists all the collections in the database in use.
boolean
key.index
document
show collections

2. changes the database on which you are working.
use <database name>
db.commandHelp("commandName")
$elemMatch
key.index

3. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
date
document
db.myCollection.ensureIndex({keypattern},[{options}])
db.getLastError()

4. Command to get help docs on a specific command at the collection level.
db.<col>.help([commandName]);
string
Object.bsonsize({document});
32-Bit Integer

5. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
db.help([commandName]);
$size
$lt
$slice

6. Unique 12-byte ID for documents.
null
object id
$in
$unset

7. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
32-Bit Integer
BSON
$pullAll
$nin

8. Clone the current database (implied by 'db') from another host.
64-bit floating point numbers
mongod
binary data
db.cloneDatabase(fromhost)

9. In BSON - represents the smallest possible value.
$push
minimum value
$size
db.getLastError()

10. set of UTF-8 characters.
Object.bsonsize({document});
null
string
$nin

11. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$gt
maximum value
64-Bit Integer
$pullAll

12. Set or list of values.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$lte
array
maximum value

13. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
string
$lte
minimum value
$nin

14. The standard number representation in the javascript shell.
embedded document
undefined
64-bit floating point numbers
$rename

15. Updates all matching documents, not just the first, that match the selector.
db.getLastError()
db.<collection>.find([properties]);
$gt
Multi-updates

16. Standard binary data type.
boolean
Cursor
code
db.commandHelp("commandName")

17. Returns one document matching the optional properties.
Cursor
db.cloneDatabase(fromhost)
db.<collection>.findOne([properties]);
$nin

18. 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.
mongod
Update Modifiers
$all
$pull

19. Command to get help docs on a specific command at the db level.
minimum value
$ne
$push
db.help([commandName]);

20. 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.
$all
regular expression
db.<col>.help([commandName]);
db.<collection>.find([properties]);

21. Adds a document to a collection.
db.<collection>.insert({document});
Update Modifiers
string
$rename

22. Used to represent both a null value and a nonexistent field.
mongod
64-bit floating point numbers
$nin
null

23. 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 },
document
embedded document
$where
$

24. Returns help information for a command.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
key.index
db.commandHelp("commandName")
code

25. Deletes documents from the collection based on the selector.
minimum value
$pull
db.<col>.remove({selector});
db.<collection>.find([properties]);

26. 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 ] } } }
$pop
db.<col>.help([commandName]);
help
$addToSet

27. Array specific conditional used to select based on the length or set-size of an array field value.
$
$not
$size
$in

28. 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.
Update Modifiers
db.runCommand({fsync:1,lock:1,async:1})
$pull
db.getLastError()

29. 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
$pull
$mod

30. 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.
$elemMatch
db.<col>.remove({selector});
$nin
$mod

31. 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 } }
Object.bsonsize({document});
$inc
Update Modifiers
$push

32. 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.
object id
Upsert
$lt
db.<collection>.insert({document});

33. command to start the mongodb process.
mongod
maximum value
minimum value
$unset

34. Update a document in the collection.
minimum value
db.<col>.update({selector},{document});
Object.bsonsize({document});
db.<col>.remove({selector});

35. Operator allowing the partial specification of fields in an embedded document in an array.
$elemMatch
date
db.getLastError()
$gte

36. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
Update Modifiers
$slice
db.<collection>.find([properties]);
$pullAll

37. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.commandHelp("commandName")
db.myCollection.ensureIndex({keypattern},[{options}])
$mod
use <database name>

38. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.<collection>.find([properties]);
db.<col>.update({selector},{document});
$gte
show collections

39. command to start the mongodb process.
date
mongod
db.<col>.remove({selector});
batch insert

40. In BSON - represents the largest possible value.
maximum value
64-Bit Integer
db.commandHelp("commandName")
key.index

41. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
regular expression
db.<collection>.findOne([properties]);
document
$gt

42. Query conditional allowing the selector to choose between more than one optional criteria.
key.index
$or
BSON
$nin

43. Clone the current database (implied by 'db') from another host.
$pullAll
regular expression
$pull
db.cloneDatabase(fromhost)

44. 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>.insert({document});
code
db.<col>.update({selector},{document});
$pop

45. command to start the mongo shell.
db.commandHelp("commandName")
mongo
document
$addToSet

46. Binary-encoded serialization of mongo documents.
batch insert
$pullAll
BSON
mongo

47. A document contained by a parent document. The embedded document is a value of a key in the parent document.
db.<collection>.insert({document});
null
db.cloneDatabase(fromhost)
embedded document

48. Contains query conditional used to check if a value contains the field value.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$nin
$in
$size

49. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$ne
code
32-Bit Integer
minimum value

50. Returns help information for a command.
Multi-updates
db.commandHelp("commandName")
$pull
db.runCommand({fsync:1,lock:1,async:1})