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. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
$pullAll
$mod
$rename
key.index

2. 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 } }
db.runCommand({fsync:1,lock:1,async:1})
$pushAll
mongod
$or

3. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$pull
Update Modifiers
$inc

4. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$pullAll
db.<collection>.find([properties]);
db.myCollection.ensureIndex({keypattern},[{options}])
$where

5. String of arbitrary bytes.
binary data
$set
$size
document

6. 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"}});
$pull
$mod
$set
db.commandHelp("commandName")

7. Adds a document to a collection.
$
db.<col>.remove({selector});
mongod
db.<collection>.insert({document});

8. 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>.find([properties]);
Upsert
$pushAll
db.<col>.help([commandName]);

9. Stored as milliseconds since the epoch.
db.cloneDatabase(fromhost)
date
$or
maximum value

10. command to start the mongo shell.
mongo
regular expression
string
BSON

11. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.getLastError()
Object.bsonsize({document});
$gte
$elemMatch

12. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
array
$lte
64-Bit Integer
db.commandHelp("commandName")

13. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
boolean
db.help([commandName]);
undefined
$ne

14. The standard number representation in the javascript shell.
string
64-bit floating point numbers
$size
$or

15. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
batch insert
$where
document

16. Deletes a given field. ex: { $unset : { field : 1} }
db.<collection>.find([properties]);
$unset
db.<col>.remove({selector});
binary data

17. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
$slice
$size
$lt
$mod

18. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$inc
$in
$slice
object id

19. 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.
array
Update Modifiers
$lte
code

20. Command to list commands and descriptions of those commands in the context of the database.
$push
null
help
mongo

21. changes the database on which you are working.
use <database name>
$pushAll
Cursor
$lte

22. 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 },
db.<collection>.insert({document});
$
db.cloneDatabase(fromhost)
db.<collection>.insert({document});

23. Javascript code. Documents can contain code as values.
mongod
$size
code
Upsert

24. Used to represent both a null value and a nonexistent field.
minimum value
array
db.myCollection.ensureIndex({keypattern},[{options}])
null

25. Returns help information for a command.
$elemMatch
db.commandHelp("commandName")
Cursor
db.<collection>.findOne([properties]);

26. 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
boolean
undefined
db.<col>.update({selector},{document});

27. Used to describe a variable as not having been initialized.
$pullAll
undefined
$addToSet
$nin

28. Binary-encoded serialization of mongo documents.
db.<collection>.find([properties]);
BSON
db.cloneDatabase(fromhost)
help

29. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
object id
db.cloneDatabase(fromhost)
$inc
regular expression

30. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
$elemMatch
use <database name>
mongod

31. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
$size
db.getLastError()
db.<col>.update({selector},{document});
Cursor

32. set of UTF-8 characters.
$gte
Upsert
string
document

33. Array specific conditional used to select based on the length or set-size of an array field value.
batch insert
BSON
maximum value
$size

34. Adds a document to a collection.
mongo
$ne
db.<collection>.insert({document});
db.<col>.help([commandName]);

35. Command to get help docs on a specific command at the collection level.
show collections
$
db.<col>.help([commandName]);
$all

36. command to start the mongo shell.
$push
mongo
$lt
show collections

37. command to start the mongodb process.
help
$not
mongod
BSON

38. Contains query conditional used to check if a value contains the field value.
$in
$pullAll
show collections
db.<col>.help([commandName]);

39. Standard binary data type.
db.runCommand({fsync:1,lock:1,async:1})
boolean
mongod
null

40. 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 ] } } }
$gte
db.cloneDatabase(fromhost)
$addToSet
code

41. Standard javascript regular expressions. These can be stored in documents
regular expression
boolean
$addToSet
$lt

42. 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.
$inc
minimum value
use <database name>
db.runCommand({fsync:1,lock:1,async:1})

43. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
date
$pullAll
minimum value
32-Bit Integer

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

45. Returns all the documents matching the optional properties.
embedded document
$gt
maximum value
db.<collection>.find([properties]);

46. changes the database on which you are working.
db.<col>.remove({selector});
Multi-updates
db.help([commandName]);
use <database name>

47. Deletes documents from the collection based on the selector.
64-Bit Integer
db.<collection>.find([properties]);
BSON
db.<col>.remove({selector});

48. A document contained by a parent document. The embedded document is a value of a key in the parent document.
batch insert
string
embedded document
db.commandHelp("commandName")

49. Returns all the documents matching the optional properties.
db.myCollection.ensureIndex({keypattern},[{options}])
db.<collection>.findOne([properties]);
array
db.<collection>.find([properties]);

50. Lists all the collections in the database in use.
null
show collections
$all
db.<col>.update({selector},{document});