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. ...
db.getLastError()
64-Bit Integer
batch insert
Update Modifiers

2. Set or list of values.
string
array
$unset
date

3. Clone the current database (implied by 'db') from another host.
db.<col>.help([commandName]);
$gte
key.index
db.cloneDatabase(fromhost)

4. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
key.index
$lt
$or

5. The standard number representation in the javascript shell.
32-Bit Integer
64-bit floating point numbers
BSON
embedded document

6. Returns all the documents matching the optional properties.
minimum value
$unset
64-Bit Integer
db.<collection>.find([properties]);

7. In BSON - represents the smallest possible value.
minimum value
null
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$pullAll

8. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
null
db.<col>.remove({selector});
$lte
Update Modifiers

9. Updates all matching documents, not just the first, that match the selector.
db.<col>.update({selector},{document});
Multi-updates
$set
object id

10. Standard javascript regular expressions. These can be stored in documents
db.<col>.update({selector},{document});
regular expression
db.<collection>.findOne([properties]);
$push

11. command to start the mongo shell.
db.<col>.update({selector},{document});
mongo
BSON
$elemMatch

12. 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.
32-Bit Integer
db.<collection>.insert({document});
$mod
$pull

13. Javascript code. Documents can contain code as values.
code
Object.bsonsize({document});
Multi-updates
db.commandHelp("commandName")

14. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
Cursor
$ne
$lt
boolean

15. In BSON - represents the largest possible value.
maximum value
db.commandHelp("commandName")
undefined
$size

16. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
64-Bit Integer
$slice
Upsert
$inc

17. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$nin
$size
db.<collection>.insert({document});
$inc

18. Returns the size of a document after it is converted to BSON from the JSON-like original.
$where
$lt
Object.bsonsize({document});
$pushAll

19. 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.
minimum value
boolean
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
db.<col>.update({selector},{document});

20. Returns help information for a command.
db.commandHelp("commandName")
$slice
regular expression
db.getLastError()

21. Binary-encoded serialization of mongo documents.
BSON
document
maximum value
Upsert

22. Query conditional allowing the selector to choose between more than one optional criteria.
$set
db.<col>.update({selector},{document});
$or
64-bit floating point numbers

23. Returns all the documents matching the optional properties.
db.<col>.help([commandName]);
$
$set
db.<collection>.find([properties]);

24. Command to list commands and descriptions of those commands in the context of the database.
minimum value
BSON
db.<col>.help([commandName]);
help

25. Update a document in the collection.
db.<col>.update({selector},{document});
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
use <database name>
$pushAll

26. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
code
$not
64-bit floating point numbers
32-Bit Integer

27. Array specific conditional used to select based on the length or set-size of an array field value.
$size
32-Bit Integer
show collections
Object.bsonsize({document});

28. 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 } }
db.getLastError()
$push
$unset
db.runCommand({fsync:1,lock:1,async:1})

29. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
document
$pushAll
$nin

30. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
use <database name>
$inc
minimum value
$elemMatch

31. String of arbitrary bytes.
$lte
$pushAll
binary data
db.<collection>.insert({document});

32. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$set
$ne
db.commandHelp("commandName")
null

33. Operator allowing the execution of arbitrary javascript as part of the selector.
$where
db.<collection>.insert({document});
$mod
$in

34. Returns help information for a command.
db.commandHelp("commandName")
db.<collection>.findOne([properties]);
$pull
$gt

35. Adds a document to a collection.
Upsert
show collections
64-bit floating point numbers
db.<collection>.insert({document});

36. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
db.<col>.help([commandName]);
$unset
$pullAll

37. Syntax used for selectors to be specific to a certain element position within an array.
32-Bit Integer
key.index
$gte
embedded document

38. Unique 12-byte ID for documents.
string
Object.bsonsize({document});
object id
null

39. Used to represent both a null value and a nonexistent field.
$ne
null
mongod
$slice

40. command to start the mongodb process.
db.cloneDatabase(fromhost)
db.<collection>.find([properties]);
mongod
$nin

41. Stored as milliseconds since the epoch.
$size
date
db.runCommand({fsync:1,lock:1,async:1})
$gt

42. Command to get help docs on a specific command at the db level.
boolean
db.help([commandName]);
$slice
$inc

43. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
null
db.getLastError()
$in
64-Bit Integer

44. Standard binary data type.
$elemMatch
boolean
regular expression
mongod

45. 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
$lte
$elemMatch
string

46. changes the database on which you are working.
use <database name>
$lt
$elemMatch
regular expression

47. command to start the mongodb process.
db.<collection>.findOne([properties]);
Upsert
help
mongod

48. changes the database on which you are working.
use <database name>
$mod
$where
$in

49. Meta query conditional used to negate the selector.
$rename
mongod
$not
binary data

50. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pushAll
db.getLastError()
$pull
$pop