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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. 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.commandHelp("commandName")
$mod
Upsert
$not

2. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
db.commandHelp("commandName")
minimum value
$lte
db.<collection>.insert({document});

3. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
mongo
boolean
$in
$slice

4. Command to list commands and descriptions of those commands in the context of the database.
help
mongod
32-Bit Integer
Object.bsonsize({document});

5. Lists all the collections in the database in use.
array
show collections
$
$pullAll

6. Used to describe a variable as not having been initialized.
undefined
array
$slice
db.commandHelp("commandName")

7. Javascript code. Documents can contain code as values.
db.help([commandName]);
document
code
32-Bit Integer

8. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$in
regular expression
db.cloneDatabase(fromhost)
$ne

9. Adds a document to a collection.
boolean
mongod
db.<col>.help([commandName]);
db.<collection>.insert({document});

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

11. Used to represent both a null value and a nonexistent field.
null
$push
$inc
undefined

12. In BSON - represents the smallest possible value.
minimum value
64-Bit Integer
$mod
db.<collection>.insert({document});

13. command to start the mongodb process.
db.<col>.update({selector},{document});
document
mongod
$push

14. 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.
$rename
db.cloneDatabase(fromhost)
mongod
db.runCommand({fsync:1,lock:1,async:1})

15. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
db.<collection>.insert({document});
$not
mongod
$inc

16. Binary-encoded serialization of mongo documents.
help
string
BSON
$addToSet

17. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.<col>.update({selector},{document});
db.getLastError()
code
Multi-updates

18. changes the database on which you are working.
$size
use <database name>
Cursor
regular expression

19. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
$where
$
db.myCollection.ensureIndex({keypattern},[{options}])

20. Data structure used to store all other data in mongo databases.
document
$set
$or
db.<col>.remove({selector});

21. Syntax used for selectors to be specific to a certain element position within an array.
key.index
$pop
db.cloneDatabase(fromhost)
$gte

22. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.<collection>.insert({document});
$pullAll
use <database name>
db.myCollection.ensureIndex({keypattern},[{options}])

23. A document contained by a parent document. The embedded document is a value of a key in the parent document.
db.runCommand({fsync:1,lock:1,async:1})
db.<collection>.find([properties]);
embedded document
null

24. Operator allowing the partial specification of fields in an embedded document in an array.
boolean
$elemMatch
db.cloneDatabase(fromhost)
db.commandHelp("commandName")

25. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
Multi-updates
64-Bit Integer
$where
BSON

26. Command to get help docs on a specific command at the collection level.
null
db.<col>.help([commandName]);
db.commandHelp("commandName")
db.getLastError()

27. 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 },
$
$in
mongo
mongo

28. The standard number representation in the javascript shell.
$
$gte
64-bit floating point numbers
document

29. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pullAll
code
$gt
$pull

30. changes the database on which you are working.
Cursor
db.runCommand({fsync:1,lock:1,async:1})
Multi-updates
use <database name>

31. Contains query conditional used to check if a value contains the field value.
mongod
$in
mongod
date

32. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
db.cloneDatabase(fromhost)
$mod
show collections

33. 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.
Update Modifiers
regular expression
help
db.<col>.update({selector},{document});

34. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
array
32-Bit Integer
$pullAll
$size

35. 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 } }
db.<collection>.find([properties]);
$pushAll
use <database name>
boolean

36. Array specific conditional allowing matching on multiple elements within an array. The operation is non strict on the sequence of the values in the passed selector array.
$pop
string
$all
$not

37. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
$where
document
Cursor
db.runCommand({fsync:1,lock:1,async:1})

38. String of arbitrary bytes.
binary data
$pushAll
code
64-bit floating point numbers

39. Operator allowing the execution of arbitrary javascript as part of the selector.
db.<col>.remove({selector});
batch insert
$where
$in

40. Command to get help docs on a specific command at the db level.
db.<col>.remove({selector});
string
$elemMatch
db.help([commandName]);

41. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$addToSet
$size
$rename

42. Meta query conditional used to negate the selector.
$not
db.<collection>.findOne([properties]);
db.<col>.update({selector},{document});
64-Bit Integer

43. In BSON - represents the largest possible value.
db.<collection>.insert({document});
db.myCollection.ensureIndex({keypattern},[{options}])
maximum value
$pop

44. 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 } }
$pop
mongod
document
$or

45. Query conditional allowing the selector to choose between more than one optional criteria.
$or
embedded document
$nin
null

46. Clone the current database (implied by 'db') from another host.
null
$rename
db.cloneDatabase(fromhost)
$gte

47. Adds a document to a collection.
$inc
db.<collection>.insert({document});
$pullAll
db.runCommand({fsync:1,lock:1,async:1})

48. Returns one document matching the optional properties.
db.<col>.remove({selector});
db.<col>.help([commandName]);
db.<collection>.findOne([properties]);
key.index

49. Returns help information for a command.
Multi-updates
$or
db.commandHelp("commandName")
db.help([commandName]);

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