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. Query conditional allowing the selector to choose between more than one optional criteria.
$all
$or
mongo
$ne

2. 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 } }
$pushAll
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$in
$push

3. 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 } }
regular expression
help
$pop
$where

4. Binary-encoded serialization of mongo documents.
null
BSON
64-Bit Integer
Upsert

5. Set or list of values.
Multi-updates
db.<col>.help([commandName]);
db.getLastError()
array

6. Standard javascript regular expressions. These can be stored in documents
$inc
$size
regular expression
db.commandHelp("commandName")

7. changes the database on which you are working.
use <database name>
db.<collection>.insert({document});
string
$lt

8. Used to describe a variable as not having been initialized.
mongo
minimum value
undefined
regular expression

9. Deletes a given field. ex: { $unset : { field : 1} }
Update Modifiers
$unset
$not
$pullAll

10. Returns help information for a command.
document
db.commandHelp("commandName")
$rename
$where

11. Operator allowing the execution of arbitrary javascript as part of the selector.
$inc
$gte
$where
Upsert

12. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
document
$slice
array
$not

13. 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"}});
regular expression
key.index
$slice
$set

14. Javascript code. Documents can contain code as values.
code
db.<col>.remove({selector});
db.help([commandName]);
document

15. Used to represent both a null value and a nonexistent field.
null
db.<collection>.find([properties]);
batch insert
$ne

16. 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.runCommand({fsync:1,lock:1,async:1})
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
use <database name>
db.cloneDatabase(fromhost)

17. The standard number representation in the javascript shell.
Update Modifiers
$lt
null
64-bit floating point numbers

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

19. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
64-Bit Integer
use <database name>
show collections
object id

20. 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.
mongod
db.<col>.update({selector},{document});
db.<col>.help([commandName]);
Upsert

21. set of UTF-8 characters.
string
$in
show collections
$size

22. 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.
minimum value
show collections
$where
$mod

23. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$lte
$inc
$pushAll
undefined

24. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
db.<col>.help([commandName]);
mongod
db.<collection>.findOne([properties]);
$lt

25. Updates all matching documents, not just the first, that match the selector.
Multi-updates
db.commandHelp("commandName")
$mod
db.commandHelp("commandName")

26. Lists all the collections in the database in use.
$push
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
regular expression
show collections

27. Special keys passed in an update call to specify complex update operations - such as alter - adding - or removing keys - and even manipulating arrays and embedded documents.
64-Bit Integer
db.runCommand({fsync:1,lock:1,async:1})
Update Modifiers
string

28. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
Upsert
db.<collection>.find([properties]);
$pullAll
minimum value

29. Returns help information for a command.
db.commandHelp("commandName")
$push
BSON
db.getLastError()

30. Command to list commands and descriptions of those commands in the context of the database.
$gt
help
undefined
minimum value

31. Returns all the documents matching the optional properties.
$gte
db.<collection>.find([properties]);
$pull
db.<collection>.insert({document});

32. Stored as milliseconds since the epoch.
32-Bit Integer
date
db.<col>.help([commandName]);
$pull

33. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
document
$set
mongod

34. changes the database on which you are working.
date
db.<col>.update({selector},{document});
use <database name>
mongo

35. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
$pushAll
db.help([commandName]);
db.myCollection.ensureIndex({keypattern},[{options}])
maximum value

36. Clone the current database (implied by 'db') from another host.
$set
db.cloneDatabase(fromhost)
$unset
$push

37. command to start the mongo shell.
$mod
mongo
Object.bsonsize({document});
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

38. Syntax used for selectors to be specific to a certain element position within an array.
undefined
$gte
key.index
$unset

39. In BSON - represents the smallest possible value.
mongod
$
minimum value
key.index

40. Meta query conditional used to negate the selector.
$nin
$not
$slice
null

41. String of arbitrary bytes.
regular expression
$set
$or
binary data

42. Operator allowing the partial specification of fields in an embedded document in an array.
BSON
$ne
Cursor
$elemMatch

43. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$gte
$pull
db.getLastError()

44. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
db.commandHelp("commandName")
$ne
$nin
$unset

45. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$in
boolean
$gt
Upsert

46. 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 ] } } }
$inc
$nin
$addToSet
undefined

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 },
$
$rename
regular expression
use <database name>

48. Unique 12-byte ID for documents.
Upsert
db.<collection>.insert({document});
object id
db.cloneDatabase(fromhost)

49. command to start the mongodb process.
$size
mongod
null
$gte

50. Update a document in the collection.
db.<col>.update({selector},{document});
$gt
undefined
use <database name>