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 used to select based on the length or set-size of an array field value.
mongod
db.commandHelp("commandName")
$gt
$size

2. 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 ] } } }
date
show collections
$addToSet
$lt

3. Stored as milliseconds since the epoch.
$mod
key.index
date
$pull

4. Deletes a given field. ex: { $unset : { field : 1} }
$unset
$where
$pushAll
regular expression

5. Returns help information for a command.
$lte
$pushAll
show collections
db.commandHelp("commandName")

6. String of arbitrary bytes.
binary data
document
BSON
date

7. Binary-encoded serialization of mongo documents.
$in
$elemMatch
$lt
BSON

8. Command to get help docs on a specific command at the db level.
64-bit floating point numbers
key.index
db.help([commandName]);
mongod

9. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
use <database name>
embedded document
$rename
Cursor

10. The standard number representation in the javascript shell.
db.commandHelp("commandName")
batch insert
64-bit floating point numbers
binary data

11. changes the database on which you are working.
use <database name>
mongod
minimum value
mongo

12. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
db.<collection>.findOne([properties]);
db.runCommand({fsync:1,lock:1,async:1})
$rename
64-Bit Integer

13. In BSON - represents the largest possible value.
maximum value
db.<col>.remove({selector});
$rename
null

14. 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 },
$where
maximum value
$
$or

15. Adds a document to a collection.
db.<col>.help([commandName]);
32-Bit Integer
minimum value
db.<collection>.insert({document});

16. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
db.runCommand({fsync:1,lock:1,async:1})
64-Bit Integer
binary data
$lt

17. Updates all matching documents, not just the first, that match the selector.
array
$pullAll
use <database name>
Multi-updates

18. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$pop
document
$ne
$push

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 } }
$addToSet
$push
$unset
db.myCollection.ensureIndex({keypattern},[{options}])

20. Meta query conditional used to negate the selector.
Object.bsonsize({document});
mongod
$push
$not

21. 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.
db.commandHelp("commandName")
binary data
$mod
db.<collection>.insert({document});

22. Adds a document to a collection.
$unset
32-Bit Integer
db.<collection>.insert({document});
show collections

23. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
date
use <database name>
$mod

24. Returns help information for a command.
object id
show collections
boolean
db.commandHelp("commandName")

25. 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 } }
date
Update Modifiers
key.index
$pop

26. Command to get help docs on a specific command at the collection level.
db.<col>.help([commandName]);
$mod
$in
use <database name>

27. 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"}});
mongo
$unset
$set
$inc

28. Data structure used to store all other data in mongo databases.
document
show collections
use <database name>
$pull

29. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
show collections
object id
db.<collection>.insert({document});
64-Bit Integer

30. Command to list commands and descriptions of those commands in the context of the database.
help
64-bit floating point numbers
db.<collection>.insert({document});
$addToSet

31. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
key.index
db.<col>.update({selector},{document});
$gt
Object.bsonsize({document});

32. Deletes documents from the collection based on the selector.
mongod
db.<col>.remove({selector});
db.cloneDatabase(fromhost)
key.index

33. Set or list of values.
array
db.<collection>.insert({document});
$push
embedded document

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

35. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
$addToSet
$nin
$elemMatch

36. Used to describe a variable as not having been initialized.
$pop
Cursor
db.<col>.remove({selector});
undefined

37. command to start the mongodb process.
mongod
$size
$where
db.myCollection.ensureIndex({keypattern},[{options}])

38. set of UTF-8 characters.
maximum value
show collections
Cursor
string

39. 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.
$push
undefined
db.<col>.help([commandName]);
$all

40. command to start the mongo shell.
db.myCollection.ensureIndex({keypattern},[{options}])
db.<col>.remove({selector});
mongo
null

41. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$push
$pull
$gt
$ne

42. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.getLastError()
show collections
64-Bit Integer
db.cloneDatabase(fromhost)

43. Standard javascript regular expressions. These can be stored in documents
$lte
db.help([commandName]);
regular expression
db.commandHelp("commandName")

44. In BSON - represents the smallest possible value.
array
$pull
db.<collection>.find([properties]);
minimum value

45. A document contained by a parent document. The embedded document is a value of a key in the parent document.
key.index
embedded document
$mod
Multi-updates

46. Deletes documents from the collection based on the selector.
embedded document
db.<col>.remove({selector});
Upsert
$ne

47. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
mongod
$elemMatch
$rename

48. Query conditional allowing the selector to choose between more than one optional criteria.
$pull
show collections
$or
string

49. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$lt
show collections
$inc
$nin

50. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
Multi-updates
$push
db.<col>.help([commandName]);
$inc