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. Used to represent both a null value and a nonexistent field.
db.<collection>.find([properties]);
$pull
$unset
null

2. Deletes a given field. ex: { $unset : { field : 1} }
64-Bit Integer
$mod
help
$unset

3. Javascript code. Documents can contain code as values.
db.cloneDatabase(fromhost)
db.help([commandName]);
code
db.<collection>.findOne([properties]);

4. Operator allowing the partial specification of fields in an embedded document in an array.
db.<col>.remove({selector});
$lt
$elemMatch
$all

5. 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 ] } } }
$ne
$addToSet
$elemMatch
$slice

6. Data structure used to store all other data in mongo databases.
document
Cursor
db.<col>.help([commandName]);
db.runCommand({fsync:1,lock:1,async:1})

7. Operator allowing the execution of arbitrary javascript as part of the selector.
$where
db.myCollection.ensureIndex({keypattern},[{options}])
show collections
Object.bsonsize({document});

8. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
maximum value
32-Bit Integer
64-bit floating point numbers
use <database name>

9. Standard javascript regular expressions. These can be stored in documents
regular expression
mongod
embedded document
$addToSet

10. Command to get help docs on a specific command at the collection level.
db.<col>.help([commandName]);
db.commandHelp("commandName")
$rename
undefined

11. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
regular expression
BSON
db.<col>.remove({selector});

12. Binary-encoded serialization of mongo documents.
undefined
$nin
BSON
mongo

13. Command to get help docs on a specific command at the db level.
batch insert
$all
db.help([commandName]);
$nin

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

15. 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"}});
$gt
embedded document
$set
db.commandHelp("commandName")

16. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$slice
show collections
mongod

17. 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 } }
$unset
$pushAll
$gte
db.<collection>.find([properties]);

18. In BSON - represents the largest possible value.
$mod
Cursor
maximum value
undefined

19. changes the database on which you are working.
db.commandHelp("commandName")
$in
use <database name>
batch insert

20. 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 } }
$push
batch insert
db.<col>.help([commandName]);
db.commandHelp("commandName")

21. 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 } }
db.<col>.remove({selector});
$pop
string
null

22. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
Update Modifiers
db.help([commandName]);
db.myCollection.ensureIndex({keypattern},[{options}])

23. Adds a document to a collection.
db.<collection>.insert({document});
db.cloneDatabase(fromhost)
use <database name>
db.<col>.update({selector},{document});

24. 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.
regular expression
db.runCommand({fsync:1,lock:1,async:1})
$size
Upsert

25. command to start the mongodb process.
mongod
Update Modifiers
$rename
$lte

26. Updates all matching documents, not just the first, that match the selector.
$elemMatch
Multi-updates
db.<collection>.find([properties]);
db.<collection>.insert({document});

27. 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.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
date
db.commandHelp("commandName")
code

28. ...
db.commandHelp("commandName")
$gt
$
batch insert

29. Query conditional allowing the selector to choose between more than one optional criteria.
string
$or
$elemMatch
64-bit floating point numbers

30. Returns help information for a command.
$mod
db.runCommand({fsync:1,lock:1,async:1})
32-Bit Integer
db.commandHelp("commandName")

31. set of UTF-8 characters.
db.<col>.remove({selector});
db.<collection>.insert({document});
Multi-updates
string

32. Set or list of values.
db.<col>.update({selector},{document});
$lt
array
Update Modifiers

33. Returns one document matching the optional properties.
db.<col>.remove({selector});
db.<collection>.findOne([properties]);
use <database name>
$pullAll

34. command to start the mongodb process.
db.myCollection.ensureIndex({keypattern},[{options}])
db.<col>.update({selector},{document});
mongod
$push

35. The standard number representation in the javascript shell.
$gt
64-bit floating point numbers
db.help([commandName]);
string

36. Array specific conditional used to select based on the length or set-size of an array field value.
db.<collection>.findOne([properties]);
db.<collection>.find([properties]);
$size
$or

37. Used to describe a variable as not having been initialized.
array
undefined
date
mongod

38. Stored as milliseconds since the epoch.
$in
date
key.index
string

39. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
mongod
$set
$nin
db.<col>.update({selector},{document});

40. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
BSON
db.getLastError()
$rename
embedded document

41. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
db.<collection>.insert({document});
db.commandHelp("commandName")
$pullAll
$slice

42. Syntax used for selectors to be specific to a certain element position within an array.
$ne
db.<collection>.findOne([properties]);
key.index
$addToSet

43. changes the database on which you are working.
db.cloneDatabase(fromhost)
use <database name>
mongo
db.<collection>.insert({document});

44. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
Cursor
$pop
db.<collection>.find([properties]);
db.commandHelp("commandName")

45. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
db.myCollection.ensureIndex({keypattern},[{options}])
$ne
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
null

46. command to start the mongo shell.
db.<col>.update({selector},{document});
db.getLastError()
Upsert
mongo

47. Meta query conditional used to negate the selector.
$not
null
$nin
$where

48. Returns all the documents matching the optional properties.
$
maximum value
db.<collection>.find([properties]);
db.<col>.update({selector},{document});

49. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$slice
$all
$rename

50. In BSON - represents the smallest possible value.
minimum value
mongo
$mod
use <database name>