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. Command to get help docs on a specific command at the collection level.
mongo
db.<col>.help([commandName]);
db.<collection>.insert({document});
$where

2. 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 } }
$lte
$pullAll
$pop
regular expression

3. changes the database on which you are working.
$unset
$or
use <database name>
string

4. Contains query conditional used to check if a value contains the field value.
db.commandHelp("commandName")
$in
maximum value
db.runCommand({fsync:1,lock:1,async:1})

5. Standard binary data type.
code
$pullAll
boolean
minimum value

6. Adds a document to a collection.
$ne
show collections
db.<collection>.findOne([properties]);
db.<collection>.insert({document});

7. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
key.index
$pullAll
$set
db.<collection>.insert({document});

8. Standard javascript regular expressions. These can be stored in documents
regular expression
$lt
db.cloneDatabase(fromhost)
64-Bit Integer

9. changes the database on which you are working.
use <database name>
$not
Update Modifiers
date

10. command to start the mongo shell.
64-bit floating point numbers
mongo
db.cloneDatabase(fromhost)
Cursor

11. 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 } }
maximum value
$nin
batch insert
$push

12. 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"}});
$push
maximum value
db.<collection>.insert({document});
$set

13. In BSON - represents the smallest possible value.
$where
minimum value
db.commandHelp("commandName")
$size

14. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$push
date
show collections
32-Bit Integer

15. Stored as milliseconds since the epoch.
db.cloneDatabase(fromhost)
date
db.myCollection.ensureIndex({keypattern},[{options}])
embedded document

16. set of UTF-8 characters.
mongo
$addToSet
$unset
string

17. Returns all the documents matching the optional properties.
$lt
$lte
batch insert
db.<collection>.find([properties]);

18. String of arbitrary bytes.
Update Modifiers
binary data
$slice
$pullAll

19. 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 },
$rename
$pop
$
$where

20. 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.
embedded document
db.runCommand({fsync:1,lock:1,async:1})
$not
db.<col>.remove({selector});

21. Operator allowing the partial specification of fields in an embedded document in an array.
array
$elemMatch
db.<collection>.find([properties]);
date

22. Array specific conditional used to select based on the length or set-size of an array field value.
$pull
$ne
$size
help

23. Returns help information for a command.
date
binary data
$size
db.commandHelp("commandName")

24. Adds a document to a collection.
use <database name>
mongo
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
db.<collection>.insert({document});

25. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
$lt
db.<collection>.insert({document});
batch insert
$elemMatch

26. The standard number representation in the javascript shell.
$addToSet
$set
64-bit floating point numbers
$rename

27. command to start the mongo shell.
Cursor
mongo
$lt
db.myCollection.ensureIndex({keypattern},[{options}])

28. 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.
help
db.<collection>.insert({document});
$mod
db.<collection>.findOne([properties]);

29. Update a document in the collection.
db.<col>.update({selector},{document});
$where
use <database name>
$addToSet

30. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
$in
mongo
db.getLastError()
$gte

31. A document contained by a parent document. The embedded document is a value of a key in the parent document.
document
use <database name>
embedded document
mongo

32. Command to list commands and descriptions of those commands in the context of the database.
help
Multi-updates
db.<col>.help([commandName]);
64-Bit Integer

33. 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 } }
key.index
$elemMatch
$pushAll
maximum value

34. Binary-encoded serialization of mongo documents.
BSON
date
$pushAll
db.cloneDatabase(fromhost)

35. Deletes documents from the collection based on the selector.
$ne
$slice
$where
db.<col>.remove({selector});

36. Returns all the documents matching the optional properties.
object id
$elemMatch
db.<collection>.find([properties]);
$pushAll

37. 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 ] } } }
db.cloneDatabase(fromhost)
use <database name>
$addToSet
date

38. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
db.<collection>.insert({document});
$slice
db.<collection>.findOne([properties]);

39. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$all
db.<collection>.findOne([properties]);
db.runCommand({fsync:1,lock:1,async:1})
64-Bit Integer

40. Data structure used to store all other data in mongo databases.
document
$lt
$gte
Upsert

41. 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.
$inc
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
use <database name>
$nin

42. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
db.commandHelp("commandName")
regular expression
$nin
embedded document

43. Operator allowing the execution of arbitrary javascript as part of the selector.
code
$where
Update Modifiers
show collections

44. ...
$all
Cursor
batch insert
object id

45. Updates all matching documents, not just the first, that match the selector.
$mod
Multi-updates
64-bit floating point numbers
$pull

46. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$nin
undefined
$ne
db.cloneDatabase(fromhost)

47. Syntax used for selectors to be specific to a certain element position within an array.
db.<col>.help([commandName]);
db.<collection>.insert({document});
key.index
64-bit floating point numbers

48. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$slice
document
$unset
$ne

49. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$elemMatch
$
Multi-updates
db.myCollection.ensureIndex({keypattern},[{options}])

50. Used to describe a variable as not having been initialized.
date
BSON
undefined
$or