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. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
array
32-Bit Integer
$all
$ne

2. command to start the mongo shell.
mongo
array
$all
BSON

3. A document contained by a parent document. The embedded document is a value of a key in the parent document.
code
embedded document
$not
$pullAll

4. 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.
$not
batch insert
$push
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

5. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$push
db.cloneDatabase(fromhost)
$pullAll
db.<collection>.find([properties]);

6. Binary-encoded serialization of mongo documents.
BSON
minimum value
Upsert
mongo

7. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$slice
Update Modifiers
$in
db.<col>.update({selector},{document});

8. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
use <database name>
object id
db.<col>.help([commandName]);
64-Bit Integer

9. Lists all the collections in the database in use.
show collections
$pullAll
regular expression
minimum value

10. Deletes documents from the collection based on the selector.
$or
$pushAll
db.<col>.remove({selector});
date

11. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$gt
$nin
string
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

12. Updates all matching documents, not just the first, that match the selector.
Multi-updates
db.<col>.update({selector},{document});
db.runCommand({fsync:1,lock:1,async:1})
help

13. 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 } }
$
$ne
db.<collection>.find([properties]);
$push

14. Clone the current database (implied by 'db') from another host.
db.<collection>.findOne([properties]);
db.runCommand({fsync:1,lock:1,async:1})
db.<col>.remove({selector});
db.cloneDatabase(fromhost)

15. 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.
$pullAll
$all
$slice
$rename

16. 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 } }
Cursor
$pushAll
BSON
$

17. Returns the size of a document after it is converted to BSON from the JSON-like original.
Object.bsonsize({document});
$all
mongod
show collections

18. Unique 12-byte ID for documents.
db.<collection>.findOne([properties]);
64-bit floating point numbers
object id
db.<col>.update({selector},{document});

19. Returns all the documents matching the optional properties.
$elemMatch
db.commandHelp("commandName")
db.<collection>.find([properties]);
db.<col>.help([commandName]);

20. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
db.commandHelp("commandName")
db.<col>.help([commandName]);
maximum value
Cursor

21. set of UTF-8 characters.
$push
$lt
$slice
string

22. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$mod
$
db.myCollection.ensureIndex({keypattern},[{options}])
$lt

23. 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.
$size
key.index
use <database name>
Update Modifiers

24. Contains query conditional used to check if a value contains the field value.
$not
$in
64-bit floating point numbers
$all

25. Operator allowing the partial specification of fields in an embedded document in an array.
$elemMatch
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$pop
$not

26. changes the database on which you are working.
Object.bsonsize({document});
$lte
64-Bit Integer
use <database name>

27. In BSON - represents the smallest possible value.
db.help([commandName]);
use <database name>
db.myCollection.ensureIndex({keypattern},[{options}])
minimum value

28. Used to describe a variable as not having been initialized.
$slice
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
undefined
mongod

29. 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 },
key.index
$
64-Bit Integer
db.help([commandName]);

30. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
object id
$rename
show collections
db.cloneDatabase(fromhost)

31. 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"}});
mongod
$elemMatch
array
$set

32. Update a document in the collection.
db.cloneDatabase(fromhost)
db.<col>.update({selector},{document});
mongod
$mod

33. Operator allowing the execution of arbitrary javascript as part of the selector.
$where
db.commandHelp("commandName")
$rename
db.cloneDatabase(fromhost)

34. Stored as milliseconds since the epoch.
64-bit floating point numbers
date
Update Modifiers
$pushAll

35. In BSON - represents the largest possible value.
$nin
$lte
$pushAll
maximum value

36. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.<col>.remove({selector});
$lt
$elemMatch
$gte

37. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
string
64-Bit Integer
$lt
db.<collection>.find([properties]);

38. Javascript code. Documents can contain code as values.
$not
code
undefined
$mod

39. Adds a document to a collection.
db.<col>.update({selector},{document});
db.myCollection.ensureIndex({keypattern},[{options}])
64-bit floating point numbers
db.<collection>.insert({document});

40. command to start the mongodb process.
$gt
mongod
$addToSet
document

41. Deletes a given field. ex: { $unset : { field : 1} }
maximum value
db.myCollection.ensureIndex({keypattern},[{options}])
mongo
$unset

42. Standard javascript regular expressions. These can be stored in documents
regular expression
db.<col>.update({selector},{document});
$pullAll
use <database name>

43. Used to represent both a null value and a nonexistent field.
$slice
db.cloneDatabase(fromhost)
null
undefined

44. Clone the current database (implied by 'db') from another host.
$unset
db.cloneDatabase(fromhost)
$or
$push

45. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
32-Bit Integer
db.runCommand({fsync:1,lock:1,async:1})
$gt
undefined

46. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
code
Cursor
$pull
array

47. Returns help information for a command.
use <database name>
binary data
db.commandHelp("commandName")
db.runCommand({fsync:1,lock:1,async:1})

48. Command to get help docs on a specific command at the db level.
db.<collection>.find([properties]);
$where
db.help([commandName]);
string

49. 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
show collections
$nin
$inc

50. ...
$size
db.<col>.help([commandName]);
batch insert
64-bit floating point numbers