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. Javascript code. Documents can contain code as values.
code
string
db.help([commandName]);
$mod

2. Adds a document to a collection.
db.<col>.update({selector},{document});
boolean
BSON
db.<collection>.insert({document});

3. Clone the current database (implied by 'db') from another host.
Update Modifiers
db.<col>.help([commandName]);
code
db.cloneDatabase(fromhost)

4. changes the database on which you are working.
64-Bit Integer
db.<collection>.find([properties]);
boolean
use <database name>

5. A document contained by a parent document. The embedded document is a value of a key in the parent document.
$ne
embedded document
db.cloneDatabase(fromhost)
$size

6. Meta query conditional used to negate the selector.
mongo
$not
undefined
mongo

7. Syntax used for selectors to be specific to a certain element position within an array.
$gte
key.index
use <database name>
Update Modifiers

8. Returns all the documents matching the optional properties.
help
$slice
mongo
db.<collection>.find([properties]);

9. 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.
Update Modifiers
$size
$lte
$elemMatch

10. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
maximum value
$ne
$unset
db.runCommand({fsync:1,lock:1,async:1})

11. Data structure used to store all other data in mongo databases.
db.<collection>.insert({document});
$unset
document
undefined

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
$pop
$set
64-bit floating point numbers

13. Deletes a given field. ex: { $unset : { field : 1} }
db.<collection>.insert({document});
$unset
db.<col>.update({selector},{document});
mongo

14. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
use <database name>
array
mongod

15. In BSON - represents the smallest possible value.
mongod
minimum value
use <database name>
$size

16. Unique 12-byte ID for documents.
mongod
$all
$gte
object id

17. 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.
document
mongo
minimum value
$mod

18. Standard javascript regular expressions. These can be stored in documents
regular expression
db.cloneDatabase(fromhost)
date
db.<col>.update({selector},{document});

19. 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 } }
$pull
$gt
$push
$ne

20. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
$lt
db.commandHelp("commandName")
use <database name>
db.getLastError()

21. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
date
Cursor
$elemMatch
$not

22. String of arbitrary bytes.
binary data
$or
$not
document

23. Lists all the collections in the database in use.
show collections
Update Modifiers
date
null

24. Returns help information for a command.
$elemMatch
db.myCollection.ensureIndex({keypattern},[{options}])
db.commandHelp("commandName")
null

25. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$where
64-bit floating point numbers
$or
32-Bit Integer

26. Stored as milliseconds since the epoch.
db.<col>.help([commandName]);
db.<col>.update({selector},{document});
date
db.cloneDatabase(fromhost)

27. Updates all matching documents, not just the first, that match the selector.
db.<col>.update({selector},{document});
$lte
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
Multi-updates

28. Deletes documents from the collection based on the selector.
regular expression
$mod
string
db.<col>.remove({selector});

29. Command to get help docs on a specific command at the collection level.
db.<col>.help([commandName]);
db.myCollection.ensureIndex({keypattern},[{options}])
$set
embedded document

30. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
mongo
32-Bit Integer
$gte
$elemMatch

31. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
show collections
batch insert
$pullAll
$addToSet

32. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
64-bit floating point numbers
$size
$nin
$where

33. In BSON - represents the largest possible value.
maximum value
$in
document
Upsert

34. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
db.<collection>.findOne([properties]);
$pull
$lte
db.<col>.help([commandName]);

35. Used to represent both a null value and a nonexistent field.
mongod
code
Update Modifiers
null

36. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
db.<collection>.findOne([properties]);
array
db.<collection>.find([properties]);
$inc

37. Contains query conditional used to check if a value contains the field value.
db.cloneDatabase(fromhost)
Upsert
$mod
$in

38. Operator allowing the partial specification of fields in an embedded document in an array.
$elemMatch
32-Bit Integer
db.<collection>.insert({document});
$where

39. 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.
undefined
db.help([commandName]);
db.<collection>.find([properties]);
db.runCommand({fsync:1,lock:1,async:1})

40. Update a document in the collection.
Update Modifiers
db.<col>.update({selector},{document});
db.cloneDatabase(fromhost)
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

41. Command to list commands and descriptions of those commands in the context of the database.
code
embedded document
help
db.runCommand({fsync:1,lock:1,async:1})

42. Array specific conditional used to select based on the length or set-size of an array field value.
db.<collection>.insert({document});
$size
mongo
object id

43. Returns all the documents matching the optional properties.
$or
db.<collection>.find([properties]);
$gte
show collections

44. command to start the mongodb process.
$pull
$or
mongod
db.<collection>.find([properties]);

45. 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 } }
mongod
db.runCommand({fsync:1,lock:1,async:1})
$pop
32-Bit Integer

46. Command to get help docs on a specific command at the db level.
mongod
db.help([commandName]);
key.index
$in

47. command to start the mongo shell.
db.commandHelp("commandName")
embedded document
mongo
minimum value

48. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.<col>.remove({selector});
db.myCollection.ensureIndex({keypattern},[{options}])
db.getLastError()
db.cloneDatabase(fromhost)

49. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
db.<col>.help([commandName]);
$unset
batch insert
$slice

50. Returns the size of a document after it is converted to BSON from the JSON-like original.
help
Object.bsonsize({document});
embedded document
db.getLastError()