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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. Deletes a given field. ex: { $unset : { field : 1} }
db.help([commandName]);
$unset
$pull
$mod

2. Command to get help docs on a specific command at the db level.
batch insert
db.help([commandName]);
$push
db.commandHelp("commandName")

3. Query conditional allowing the selector to choose between more than one optional criteria.
$or
64-Bit Integer
db.myCollection.ensureIndex({keypattern},[{options}])
mongo

4. Data structure used to store all other data in mongo databases.
db.<collection>.findOne([properties]);
64-bit floating point numbers
document
mongod

5. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
$
$inc
db.<col>.remove({selector});
Object.bsonsize({document});

6. command to start the mongo shell.
$slice
undefined
db.<col>.update({selector},{document});
mongo

7. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$gte
$lt
$not

8. set of UTF-8 characters.
string
batch insert
$pull
db.<collection>.findOne([properties]);

9. Returns one document matching the optional properties.
$gt
db.<collection>.findOne([properties]);
db.<collection>.insert({document});
$pullAll

10. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$addToSet
$lte
$not
$nin

11. 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 },
help
db.<collection>.find([properties]);
$
BSON

12. Binary-encoded serialization of mongo documents.
$rename
Update Modifiers
BSON
64-Bit Integer

13. Returns the size of a document after it is converted to BSON from the JSON-like original.
$push
Object.bsonsize({document});
$lte
$addToSet

14. Command to get help docs on a specific command at the collection level.
mongo
use <database name>
db.<col>.help([commandName]);
db.runCommand({fsync:1,lock:1,async:1})

15. Used to describe a variable as not having been initialized.
db.<col>.remove({selector});
undefined
64-bit floating point numbers
$gt

16. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
Multi-updates
$ne
64-Bit Integer
Cursor

17. Command to list commands and descriptions of those commands in the context of the database.
regular expression
64-bit floating point numbers
db.commandHelp("commandName")
help

18. command to start the mongo shell.
$set
db.<collection>.insert({document});
$lte
mongo

19. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$slice
db.<collection>.find([properties]);
Update Modifiers
code

20. Unique 12-byte ID for documents.
db.commandHelp("commandName")
$
$inc
object id

21. Returns help information for a command.
$pullAll
$inc
$set
db.commandHelp("commandName")

22. Returns all the documents matching the optional properties.
$unset
db.<collection>.find([properties]);
show collections
$pop

23. changes the database on which you are working.
64-Bit Integer
use <database name>
mongo
mongo

24. Meta query conditional used to negate the selector.
$not
mongo
db.<col>.remove({selector});
db.cloneDatabase(fromhost)

25. The standard number representation in the javascript shell.
db.<collection>.insert({document});
$unset
64-bit floating point numbers
$pop

26. 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.<collection>.find([properties]);
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
boolean
key.index

27. Stored as milliseconds since the epoch.
$inc
date
batch insert
db.<collection>.find([properties]);

28. 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.getLastError()
db.runCommand({fsync:1,lock:1,async:1})
$pullAll
$unset

29. 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"}});
batch insert
$set
minimum value
db.<collection>.find([properties]);

30. Update a document in the collection.
db.<col>.update({selector},{document});
$gt
$
$set

31. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.getLastError()
code
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
mongo

32. changes the database on which you are working.
binary data
use <database name>
db.<col>.remove({selector});
$elemMatch

33. Set or list of values.
help
mongo
array
date

34. Standard binary data type.
boolean
db.<collection>.insert({document});
$size
$rename

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 } }
$pushAll
date
64-Bit Integer
32-Bit Integer

36. Used to represent both a null value and a nonexistent field.
null
help
undefined
$mod

37. Syntax used for selectors to be specific to a certain element position within an array.
date
$or
$unset
key.index

38. Updates all matching documents, not just the first, that match the selector.
key.index
Multi-updates
help
$unset

39. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
Upsert
null
$unset

40. In BSON - represents the smallest possible value.
minimum value
$where
maximum value
db.getLastError()

41. 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.
db.<collection>.findOne([properties]);
embedded document
$all
$nin

42. Adds a document to a collection.
boolean
db.commandHelp("commandName")
Upsert
db.<collection>.insert({document});

43. Operator allowing the execution of arbitrary javascript as part of the selector.
$set
db.<collection>.find([properties]);
mongod
$where

44. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
mongo
$nin
regular expression
db.<collection>.insert({document});

45. Adds a document to a collection.
$nin
db.<collection>.insert({document});
$pullAll
null

46. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pull
$pop
mongo
binary data

47. Clone the current database (implied by 'db') from another host.
binary data
db.cloneDatabase(fromhost)
mongod
$all

48. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
undefined
boolean
$ne
db.cloneDatabase(fromhost)

49. Contains query conditional used to check if a value contains the field value.
code
null
$ne
$in

50. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
show collections
minimum value
document