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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. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
help
array
batch insert

2. Updates all matching documents, not just the first, that match the selector.
$push
object id
help
Multi-updates

3. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
$in
db.<col>.update({selector},{document});
minimum value

4. 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 ] } } }
$where
embedded document
$addToSet
array

5. Used to represent both a null value and a nonexistent field.
array
Multi-updates
$push
null

6. Standard binary data type.
embedded document
db.<collection>.find([properties]);
db.<col>.help([commandName]);
boolean

7. 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 } }
$pop
$pullAll
db.<collection>.insert({document});
32-Bit Integer

8. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
code
db.help([commandName]);
db.<collection>.insert({document});
$pull

9. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
$ne
null
$nin

10. 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
minimum value
db.<collection>.find([properties]);
$size

11. 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.
64-bit floating point numbers
boolean
Update Modifiers
$in

12. In BSON - represents the largest possible value.
db.<col>.remove({selector});
use <database name>
maximum value
db.commandHelp("commandName")

13. Operator allowing the execution of arbitrary javascript as part of the selector.
embedded document
batch insert
$inc
$where

14. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
db.getLastError()
undefined
$or
32-Bit Integer

15. 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 } }
$push
$pushAll
db.commandHelp("commandName")
batch insert

16. Command to list commands and descriptions of those commands in the context of the database.
$slice
boolean
help
binary data

17. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$set
regular expression
$pullAll
64-bit floating point numbers

18. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.myCollection.ensureIndex({keypattern},[{options}])
mongo
embedded document
regular expression

19. Deletes a given field. ex: { $unset : { field : 1} }
use <database name>
null
db.help([commandName]);
$unset

20. Contains query conditional used to check if a value contains the field value.
$in
db.runCommand({fsync:1,lock:1,async:1})
null
db.commandHelp("commandName")

21. 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
db.myCollection.ensureIndex({keypattern},[{options}])
$addToSet
regular expression

22. Deletes documents from the collection based on the selector.
$slice
db.<col>.remove({selector});
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$where

23. Returns help information for a command.
array
db.commandHelp("commandName")
$where
db.<collection>.findOne([properties]);

24. Command to get help docs on a specific command at the db level.
db.<col>.remove({selector});
$unset
db.help([commandName]);
batch insert

25. Clone the current database (implied by 'db') from another host.
Cursor
db.cloneDatabase(fromhost)
64-bit floating point numbers
document

26. Lists all the collections in the database in use.
show collections
$mod
Update Modifiers
$

27. Returns the size of a document after it is converted to BSON from the JSON-like original.
string
db.<col>.help([commandName]);
Object.bsonsize({document});
maximum value

28. Array specific conditional used to select based on the length or set-size of an array field value.
$size
$gt
db.commandHelp("commandName")
64-bit floating point numbers

29. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
array
$nin
$all
binary data

30. Unique 12-byte ID for documents.
$unset
db.help([commandName]);
$rename
object id

31. Stored as milliseconds since the epoch.
date
$pushAll
$gt
db.<col>.remove({selector});

32. String of arbitrary bytes.
binary data
db.<collection>.insert({document});
minimum value
use <database name>

33. Meta query conditional used to negate the selector.
$not
db.<col>.help([commandName]);
use <database name>
db.<col>.update({selector},{document});

34. set of UTF-8 characters.
db.getLastError()
$elemMatch
Upsert
string

35. 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 },
$
Object.bsonsize({document});
Update Modifiers
64-Bit Integer

36. command to start the mongodb process.
mongod
$pop
object id
$addToSet

37. ...
32-Bit Integer
$pushAll
batch insert
$lte

38. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
boolean
db.<collection>.find([properties]);
key.index

39. Update a document in the collection.
null
$size
string
db.<col>.update({selector},{document});

40. changes the database on which you are working.
use <database name>
$lte
$size
db.<collection>.insert({document});

41. Returns help information for a command.
regular expression
array
db.<collection>.insert({document});
db.commandHelp("commandName")

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

43. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
regular expression
db.cloneDatabase(fromhost)
$ne
db.commandHelp("commandName")

44. command to start the mongo shell.
db.<collection>.insert({document});
mongo
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
string

45. 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
$pull
db.<collection>.insert({document});
$all

46. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
$gt
binary data
Cursor
$mod

47. Used to describe a variable as not having been initialized.
$rename
undefined
$in
$nin

48. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$gte
64-bit floating point numbers
document
64-Bit Integer

49. Binary-encoded serialization of mongo documents.
db.commandHelp("commandName")
BSON
db.cloneDatabase(fromhost)
$pullAll

50. The standard number representation in the javascript shell.
$size
regular expression
64-bit floating point numbers
db.<col>.help([commandName]);