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. Updates all matching documents, not just the first, that match the selector.
db.getLastError()
string
$where
Multi-updates

2. The standard number representation in the javascript shell.
$pop
db.commandHelp("commandName")
$lte
64-bit floating point numbers

3. Binary-encoded serialization of mongo documents.
$in
mongo
db.cloneDatabase(fromhost)
BSON

4. command to start the mongo shell.
Upsert
undefined
db.<col>.remove({selector});
mongo

5. Syntax used for selectors to be specific to a certain element position within an array.
key.index
db.<collection>.find([properties]);
minimum value
$gte

6. Clone the current database (implied by 'db') from another host.
64-bit floating point numbers
db.<collection>.findOne([properties]);
db.cloneDatabase(fromhost)
32-Bit Integer

7. Operator allowing the execution of arbitrary javascript as part of the selector.
$gt
$where
64-Bit Integer
mongo

8. changes the database on which you are working.
maximum value
document
$rename
use <database name>

9. 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
32-Bit Integer
db.<collection>.findOne([properties]);
document

10. Standard binary data type.
64-bit floating point numbers
mongod
boolean
$set

11. Update a document in the collection.
$push
mongo
$rename
db.<col>.update({selector},{document});

12. Command to get help docs on a specific command at the db level.
db.myCollection.ensureIndex({keypattern},[{options}])
db.help([commandName]);
db.<collection>.findOne([properties]);
$slice

13. command to start the mongodb process.
mongod
$size
$
$elemMatch

14. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
Upsert
db.runCommand({fsync:1,lock:1,async:1})
$lt
key.index

15. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
$in
help
64-bit floating point numbers

16. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
date
db.runCommand({fsync:1,lock:1,async:1})
db.<collection>.findOne([properties]);
$lte

17. 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.<collection>.findOne([properties]);
$mod
mongo
Update Modifiers

18. Used to represent both a null value and a nonexistent field.
null
64-Bit Integer
use <database name>
object id

19. Query conditional allowing the selector to choose between more than one optional criteria.
use <database name>
$lte
32-Bit Integer
$or

20. Set or list of values.
key.index
db.<col>.help([commandName]);
db.commandHelp("commandName")
array

21. Array specific conditional used to select based on the length or set-size of an array field value.
db.<collection>.insert({document});
$pullAll
$size
$slice

22. Adds a document to a collection.
BSON
embedded document
db.<collection>.insert({document});
$gte

23. Contains query conditional used to check if a value contains the field value.
$in
key.index
mongod
undefined

24. 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.
mongod
db.<col>.remove({selector});
Update Modifiers
object id

25. Returns help information for a command.
$elemMatch
binary data
db.commandHelp("commandName")
$pullAll

26. 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
db.<collection>.insert({document});
$or
$pop

27. In BSON - represents the smallest possible value.
minimum value
$push
db.<col>.remove({selector});
document

28. Stored as milliseconds since the epoch.
date
$slice
boolean
document

29. command to start the mongodb process.
$lt
$set
db.runCommand({fsync:1,lock:1,async:1})
mongod

30. Meta query conditional used to negate the selector.
db.cloneDatabase(fromhost)
array
$nin
$not

31. Data structure used to store all other data in mongo databases.
$inc
64-bit floating point numbers
document
use <database name>

32. Clone the current database (implied by 'db') from another host.
$push
$lte
db.<col>.help([commandName]);
db.cloneDatabase(fromhost)

33. Deletes a given field. ex: { $unset : { field : 1} }
$unset
$pushAll
Multi-updates
32-Bit Integer

34. Returns help information for a command.
db.<col>.update({selector},{document});
db.commandHelp("commandName")
$set
BSON

35. String of arbitrary bytes.
use <database name>
$ne
object id
binary data

36. 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
binary data

37. ...
Update Modifiers
batch insert
key.index
db.<collection>.insert({document});

38. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
help
batch insert
use <database name>
$slice

39. 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 ] } } }
help
Object.bsonsize({document});
maximum value
$addToSet

40. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.<collection>.findOne([properties]);
db.myCollection.ensureIndex({keypattern},[{options}])
$size
$pushAll

41. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
Multi-updates
$inc
object id
mongod

42. Operator allowing the partial specification of fields in an embedded document in an array.
key.index
mongo
date
$elemMatch

43. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
$addToSet
$gte
binary data
db.help([commandName]);

44. Command to list commands and descriptions of those commands in the context of the database.
$
$where
64-Bit Integer
help

45. Lists all the collections in the database in use.
Cursor
64-bit floating point numbers
$pop
show collections

46. 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.
boolean
32-Bit Integer
Upsert
null

47. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
db.commandHelp("commandName")
mongo
$pull
db.cloneDatabase(fromhost)

48. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
mongo
32-Bit Integer
$set
$all

49. 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 },
maximum value
BSON
db.cloneDatabase(fromhost)
$

50. Returns all the documents matching the optional properties.
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
db.<collection>.find([properties]);
Object.bsonsize({document});
use <database name>