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. 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
$or
$size
$where

2. Javascript code. Documents can contain code as values.
$gte
code
db.<collection>.insert({document});
help

3. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
BSON
$
64-Bit Integer
embedded document

4. Standard javascript regular expressions. These can be stored in documents
key.index
Multi-updates
regular expression
db.<col>.remove({selector});

5. Stored as milliseconds since the epoch.
$lt
date
$addToSet
$in

6. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
db.help([commandName]);
undefined
regular expression
$pullAll

7. command to start the mongo shell.
mongo
32-Bit Integer
db.<col>.remove({selector});
Update Modifiers

8. 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.
db.commandHelp("commandName")
BSON
db.runCommand({fsync:1,lock:1,async:1})
$size

9. Returns help information for a command.
db.cloneDatabase(fromhost)
$set
object id
db.commandHelp("commandName")

10. Adds a document to a collection.
$pushAll
db.<collection>.insert({document});
binary data
db.<col>.update({selector},{document});

11. Meta query conditional used to negate the selector.
db.commandHelp("commandName")
batch insert
db.<collection>.find([properties]);
$not

12. Operator allowing the partial specification of fields in an embedded document in an array.
$where
$slice
binary data
$elemMatch

13. Used to represent both a null value and a nonexistent field.
db.commandHelp("commandName")
null
$size
$unset

14. Data structure used to store all other data in mongo databases.
document
Object.bsonsize({document});
Multi-updates
$pop

15. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$pushAll
$ne
db.myCollection.ensureIndex({keypattern},[{options}])
show collections

16. ...
batch insert
null
db.<collection>.find([properties]);
Object.bsonsize({document});

17. 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 } }
null
$or
$push
$

18. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
db.cloneDatabase(fromhost)
maximum value
64-Bit Integer
32-Bit Integer

19. set of UTF-8 characters.
string
$pullAll
null
use <database name>

20. Clone the current database (implied by 'db') from another host.
Multi-updates
undefined
db.cloneDatabase(fromhost)
db.<collection>.findOne([properties]);

21. changes the database on which you are working.
$mod
$lte
use <database name>
object id

22. Returns help information for a command.
db.commandHelp("commandName")
db.<col>.remove({selector});
batch insert
$gte

23. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
date
$addToSet
mongod

24. In BSON - represents the largest possible value.
maximum value
db.<collection>.find([properties]);
date
Cursor

25. 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"}});
Update Modifiers
$set
$inc
db.<collection>.insert({document});

26. Returns the size of a document after it is converted to BSON from the JSON-like original.
Object.bsonsize({document});
$ne
db.commandHelp("commandName")
show collections

27. Contains query conditional used to check if a value contains the field value.
db.<collection>.find([properties]);
$in
Upsert
$all

28. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
db.<collection>.insert({document});
$addToSet
Object.bsonsize({document});
$slice

29. Query conditional allowing the selector to choose between more than one optional criteria.
$rename
$or
embedded document
maximum value

30. Standard binary data type.
$inc
$push
Object.bsonsize({document});
boolean

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

32. command to start the mongodb process.
db.<col>.update({selector},{document});
mongod
db.runCommand({fsync:1,lock:1,async:1})
db.commandHelp("commandName")

33. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.getLastError()
boolean
$gt
Update Modifiers

34. command to start the mongo shell.
$slice
mongo
$not
db.runCommand({fsync:1,lock:1,async:1})

35. 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
$gt
$slice
db.commandHelp("commandName")

36. 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 } }
key.index
Update Modifiers
$pop
mongo

37. Returns one document matching the optional properties.
db.<col>.remove({selector});
db.cloneDatabase(fromhost)
db.<collection>.findOne([properties]);
batch insert

38. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
db.help([commandName]);
$nin
undefined

39. The standard number representation in the javascript shell.
db.myCollection.ensureIndex({keypattern},[{options}])
BSON
db.<collection>.find([properties]);
64-bit floating point numbers

40. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
$in
$pull
db.<collection>.findOne([properties]);

41. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
batch insert
minimum value
use <database name>
$gt

42. A document contained by a parent document. The embedded document is a value of a key in the parent document.
array
embedded document
document
db.help([commandName]);

43. Command to get help docs on a specific command at the db level.
64-bit floating point numbers
$unset
batch insert
db.help([commandName]);

44. Command to get help docs on a specific command at the collection level.
db.<col>.help([commandName]);
Cursor
db.<col>.remove({selector});
$nin

45. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$inc
help
32-Bit Integer
db.myCollection.ensureIndex({keypattern},[{options}])

46. Updates all matching documents, not just the first, that match the selector.
32-Bit Integer
Multi-updates
db.getLastError()
null

47. 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 },
use <database name>
$
$where
Update Modifiers

48. Update a document in the collection.
mongo
$size
db.<collection>.find([properties]);
db.<col>.update({selector},{document});

49. changes the database on which you are working.
help
$or
Upsert
use <database name>

50. 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.
$mod
minimum value
db.commandHelp("commandName")
string