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

2. 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.
Update Modifiers
null
mongo
$mod

3. command to start the mongodb process.
date
mongod
$where
$pop

4. Adds a document to a collection.
db.<collection>.insert({document});
$where
mongod
null

5. Javascript code. Documents can contain code as values.
$size
code
minimum value
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

6. Deletes documents from the collection based on the selector.
db.<col>.remove({selector});
db.<col>.update({selector},{document});
code
$gt

7. String of arbitrary bytes.
mongod
db.runCommand({fsync:1,lock:1,async:1})
binary data
db.<col>.remove({selector});

8. Returns one document matching the optional properties.
minimum value
$set
$size
db.<collection>.findOne([properties]);

9. 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.
$pull
Cursor
use <database name>
Update Modifiers

10. Update a document in the collection.
document
db.<col>.update({selector},{document});
embedded document
db.<collection>.find([properties]);

11. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$slice
array
Upsert
db.runCommand({fsync:1,lock:1,async:1})

12. Adds a document to a collection.
undefined
db.<collection>.insert({document});
db.<collection>.find([properties]);
$lt

13. Stored as milliseconds since the epoch.
db.cloneDatabase(fromhost)
$pushAll
date
db.<collection>.find([properties]);

14. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
$inc
db.<collection>.find([properties]);
minimum value
db.<col>.remove({selector});

15. Set or list of values.
string
array
db.<collection>.insert({document});
$gte

16. ...
mongod
db.<col>.help([commandName]);
batch insert
$gte

17. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.cloneDatabase(fromhost)
$gt
$gte
Upsert

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

19. Returns help information for a command.
db.<col>.help([commandName]);
db.commandHelp("commandName")
db.getLastError()
$

20. Command to list commands and descriptions of those commands in the context of the database.
help
mongod
db.commandHelp("commandName")
db.cloneDatabase(fromhost)

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

22. Updates all matching documents, not just the first, that match the selector.
string
$lte
use <database name>
Multi-updates

23. Operator allowing the partial specification of fields in an embedded document in an array.
$inc
$elemMatch
Update Modifiers
db.help([commandName]);

24. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
64-bit floating point numbers
array
db.runCommand({fsync:1,lock:1,async:1})
$pull

25. changes the database on which you are working.
$in
$gte
use <database name>
mongo

26. Meta query conditional used to negate the selector.
db.<col>.help([commandName]);
$slice
$not
$set

27. 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.
$pull
$or
code
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);

28. Unique 12-byte ID for documents.
object id
mongod
Object.bsonsize({document});
db.<col>.remove({selector});

29. Data structure used to store all other data in mongo databases.
BSON
$lte
64-bit floating point numbers
document

30. 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 },
$slice
32-Bit Integer
code
$

31. 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 } }
$ne
db.runCommand({fsync:1,lock:1,async:1})
$push
$elemMatch

32. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
db.<collection>.insert({document});
$addToSet
db.commandHelp("commandName")
32-Bit Integer

33. Syntax used for selectors to be specific to a certain element position within an array.
$slice
key.index
db.help([commandName]);
$size

34. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
help
$ne
mongod
db.commandHelp("commandName")

35. Binary-encoded serialization of mongo documents.
db.<col>.remove({selector});
db.runCommand({fsync:1,lock:1,async:1})
undefined
BSON

36. Array specific conditional used to select based on the length or set-size of an array field value.
Object.bsonsize({document});
help
$size
$lt

37. Command to get help docs on a specific command at the db level.
$unset
db.help([commandName]);
db.<collection>.findOne([properties]);
$in

38. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
mongo
mongod
db.getLastError()
batch insert

39. Used to describe a variable as not having been initialized.
batch insert
undefined
$set
Multi-updates

40. Operator allowing the execution of arbitrary javascript as part of the selector.
db.runCommand({fsync:1,lock:1,async:1})
db.commandHelp("commandName")
$where
db.<col>.update({selector},{document});

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

42. 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 ] } } }
$where
db.myCollection.ensureIndex({keypattern},[{options}])
$nin
$addToSet

43. Returns the size of a document after it is converted to BSON from the JSON-like original.
$inc
Object.bsonsize({document});
32-Bit Integer
$rename

44. command to start the mongodb process.
object id
64-Bit Integer
show collections
mongod

45. A document contained by a parent document. The embedded document is a value of a key in the parent document.
embedded document
db.getLastError()
$lt
db.myCollection.ensureIndex({keypattern},[{options}])

46. Used to represent both a null value and a nonexistent field.
$in
$
binary data
null

47. Command to get help docs on a specific command at the collection level.
null
$mod
batch insert
db.<col>.help([commandName]);

48. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$gt
use <database name>
minimum value
$rename

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

50. Deletes a given field. ex: { $unset : { field : 1} }
show collections
$size
$unset
64-bit floating point numbers