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. Operator allowing the execution of arbitrary javascript as part of the selector.
db.<collection>.find([properties]);
$where
$lt
$size

2. Adds a document to a collection.
undefined
db.<collection>.findOne([properties]);
db.<collection>.insert({document});
$mod

3. Used to describe a variable as not having been initialized.
$pull
minimum value
undefined
string

4. Deletes documents from the collection based on the selector.
db.commandHelp("commandName")
db.<col>.remove({selector});
mongod
maximum value

5. 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
BSON
mongod
$pop

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

7. 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
Upsert
Update Modifiers
$elemMatch

8. Query conditional allowing the selector to choose between more than one optional criteria.
Object.bsonsize({document});
$or
$lt
$pull

9. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
Cursor
$push
key.index
show collections

10. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$ne
db.commandHelp("commandName")
BSON

11. command to start the mongo shell.
db.<col>.remove({selector});
32-Bit Integer
$not
mongo

12. Returns help information for a command.
db.<col>.remove({selector});
db.commandHelp("commandName")
Object.bsonsize({document});
$pushAll

13. Command to get help docs on a specific command at the collection level.
Update Modifiers
$elemMatch
64-bit floating point numbers
db.<col>.help([commandName]);

14. set of UTF-8 characters.
$nin
code
$gt
string

15. Returns all the documents matching the optional properties.
$elemMatch
Update Modifiers
help
db.<collection>.find([properties]);

16. command to start the mongodb process.
mongod
Cursor
$push
$pull

17. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$push
64-Bit Integer
$pull
mongo

18. Standard binary data type.
boolean
$pullAll
date
$mod

19. Stored as milliseconds since the epoch.
date
$mod
$size
db.cloneDatabase(fromhost)

20. changes the database on which you are working.
db.<collection>.findOne([properties]);
boolean
use <database name>
$ne

21. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
32-Bit Integer
db.<collection>.insert({document});
db.help([commandName]);

22. Deletes a given field. ex: { $unset : { field : 1} }
db.getLastError()
key.index
document
$unset

23. 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.<col>.update({selector},{document});
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
db.<collection>.find([properties]);
maximum value

24. Returns the size of a document after it is converted to BSON from the JSON-like original.
Update Modifiers
Upsert
Object.bsonsize({document});
minimum value

25. Deletes documents from the collection based on the selector.
db.cloneDatabase(fromhost)
date
$in
db.<col>.remove({selector});

26. changes the database on which you are working.
db.myCollection.ensureIndex({keypattern},[{options}])
db.<col>.remove({selector});
$mod
use <database name>

27. Updates all matching documents, not just the first, that match the selector.
Multi-updates
$elemMatch
db.myCollection.ensureIndex({keypattern},[{options}])
$mod

28. Data structure used to store all other data in mongo databases.
document
help
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
Cursor

29. 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 ] } } }
$addToSet
undefined
mongo
null

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.
$pushAll
$mod
$elemMatch
mongod

31. Command to get help docs on a specific command at the db level.
null
minimum value
$gte
db.help([commandName]);

32. Used to represent both a null value and a nonexistent field.
null
minimum value
$in
db.help([commandName]);

33. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
regular expression
$or
$size
$inc

34. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
date
db.runCommand({fsync:1,lock:1,async:1})
string
$lt

35. Array specific conditional used to select based on the length or set-size of an array field value.
db.<col>.update({selector},{document});
boolean
$size
document

36. Unique 12-byte ID for documents.
date
db.<collection>.insert({document});
mongo
object id

37. command to start the mongodb process.
db.<col>.remove({selector});
mongod
mongo
db.<collection>.findOne([properties]);

38. 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"}});
$set
$rename
$nin
$pull

39. Adds a document to a collection.
db.<collection>.insert({document});
$unset
maximum value
db.commandHelp("commandName")

40. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$nin
code
db.cloneDatabase(fromhost)
undefined

41. Javascript code. Documents can contain code as values.
code
show collections
64-Bit Integer
$rename

42. 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 },
$inc
$
$or
use <database name>

43. A document contained by a parent document. The embedded document is a value of a key in the parent document.
Object.bsonsize({document});
32-Bit Integer
embedded document
db.<collection>.find([properties]);

44. 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.
$pullAll
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$lt
Upsert

45. Returns one document matching the optional properties.
$mod
mongo
$pop
db.<collection>.findOne([properties]);

46. Standard javascript regular expressions. These can be stored in documents
mongo
$unset
regular expression
help

47. Returns help information for a command.
code
db.<collection>.insert({document});
help
db.commandHelp("commandName")

48. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
code
undefined
db.commandHelp("commandName")

49. In BSON - represents the largest possible value.
maximum value
mongo
$mod
$pushAll

50. command to start the mongo shell.
32-Bit Integer
$where
mongo
$slice