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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. 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 } }
boolean
BSON
help
$pushAll

2. Returns help information for a command.
db.getLastError()
$not
$elemMatch
db.commandHelp("commandName")

3. changes the database on which you are working.
Cursor
use <database name>
binary data
Multi-updates

4. Adds a document to a collection.
db.<collection>.insert({document});
$lt
$slice
db.<collection>.findOne([properties]);

5. Meta query conditional used to negate the selector.
$not
date
db.<col>.help([commandName]);
show collections

6. Operator allowing the execution of arbitrary javascript as part of the selector.
$lt
db.help([commandName]);
$where
$pushAll

7. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
db.commandHelp("commandName")
$mod
date
Cursor

8. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
Upsert
$set
$slice
$lt

9. 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 } }
null
undefined
$pop
$ne

10. Deletes documents from the collection based on the selector.
$pop
db.<col>.remove({selector});
$pullAll
use <database name>

11. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$gt
$pullAll
db.myCollection.ensureIndex({keypattern},[{options}])
binary data

12. 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 ] } } }
32-Bit Integer
$addToSet
embedded document
object id

13. Contains query conditional used to check if a value contains the field value.
db.<collection>.find([properties]);
$in
db.cloneDatabase(fromhost)
show collections

14. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$set
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$lte
db.commandHelp("commandName")

15. 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.
$in
Update Modifiers
Multi-updates
$nin

16. Standard javascript regular expressions. These can be stored in documents
regular expression
$in
use <database name>
maximum value

17. Binary-encoded serialization of mongo documents.
$all
db.<collection>.find([properties]);
db.<collection>.find([properties]);
BSON

18. In BSON - represents the largest possible value.
$push
$nin
maximum value
$rename

19. Lists all the collections in the database in use.
show collections
maximum value
$
key.index

20. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
$lte
help
string
$gte

21. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
$rename
$gt
$pullAll

22. Updates all matching documents, not just the first, that match the selector.
$in
db.cloneDatabase(fromhost)
$elemMatch
Multi-updates

23. Adds a document to a collection.
binary data
db.<collection>.insert({document});
$ne
$pushAll

24. Returns all the documents matching the optional properties.
mongo
mongo
code
db.<collection>.find([properties]);

25. 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
$push
minimum value
$ne

26. command to start the mongodb process.
db.help([commandName]);
mongod
$elemMatch
Upsert

27. Data structure used to store all other data in mongo databases.
db.<col>.remove({selector});
date
document
Object.bsonsize({document});

28. command to start the mongodb process.
Multi-updates
Update Modifiers
mongod
db.<col>.help([commandName]);

29. Command to get help docs on a specific command at the collection level.
Update Modifiers
use <database name>
regular expression
db.<col>.help([commandName]);

30. set of UTF-8 characters.
string
$gt
array
Update Modifiers

31. 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.
Upsert
$unset
help
db.<collection>.findOne([properties]);

32. In BSON - represents the smallest possible value.
undefined
mongod
db.cloneDatabase(fromhost)
minimum value

33. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
32-Bit Integer
batch insert
db.<col>.help([commandName]);
$pullAll

34. Returns all the documents matching the optional properties.
document
$pull
help
db.<collection>.find([properties]);

35. Standard binary data type.
boolean
regular expression
32-Bit Integer
minimum value

36. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
help
$nin
db.myCollection.ensureIndex({keypattern},[{options}])
db.commandHelp("commandName")

37. Stored as milliseconds since the epoch.
date
Cursor
show collections
db.help([commandName]);

38. Javascript code. Documents can contain code as values.
show collections
boolean
Multi-updates
code

39. Used to represent both a null value and a nonexistent field.
$gte
null
code
Multi-updates

40. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
Upsert
regular expression
BSON
$pull

41. 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
$set
batch insert
db.commandHelp("commandName")

42. Command to get help docs on a specific command at the db level.
db.help([commandName]);
BSON
db.<collection>.find([properties]);
use <database name>

43. Update a document in the collection.
db.<col>.update({selector},{document});
db.commandHelp("commandName")
$rename
$gte

44. 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.
db.myCollection.ensureIndex({keypattern},[{options}])
db.runCommand({fsync:1,lock:1,async:1})
undefined
Cursor

45. Used to describe a variable as not having been initialized.
undefined
Update Modifiers
db.commandHelp("commandName")
$where

46. Array specific conditional used to select based on the length or set-size of an array field value.
$mod
$size
$all
$addToSet

47. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
db.<collection>.insert({document});
db.commandHelp("commandName")
help
$rename

48. changes the database on which you are working.
Update Modifiers
$in
use <database name>
$or

49. 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.
mongod
$pop
$mod
db.myCollection.ensureIndex({keypattern},[{options}])

50. Deletes documents from the collection based on the selector.
db.commandHelp("commandName")
db.<col>.remove({selector});
$all
db.<collection>.find([properties]);