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Test your basic knowledge |
Mongo Db
Start Test
Study First
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. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$mod
string
$gt
Object.bsonsize({document});
2. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
$rename
64-bit floating point numbers
use <database name>
key.index
3. Update modifier that set the value of a key and if the key does not exist, it will create the key. ex: db.<col>.update({selector},{"$set":{"someKey":"someValue"}});
$set
$elemMatch
$slice
document
4. Command to get help docs on a specific command at the collection level.
$pullAll
Update Modifiers
show collections
db.<col>.help([commandName]);
5. Lists all the collections in the database in use.
binary data
$nin
$push
show collections
6. Set or list of values.
key.index
show collections
array
$set
7. Returns help information for a command.
mongo
db.commandHelp("commandName")
$slice
db.<collection>.insert({document});
8. Stored as milliseconds since the epoch.
date
db.<collection>.insert({document});
help
mongo
9. command to start the mongo shell.
minimum value
64-Bit Integer
code
mongo
10. Data structure used to store all other data in mongo databases.
db.cloneDatabase(fromhost)
db.myCollection.ensureIndex({keypattern},[{options}])
db.<col>.remove({selector});
document
11. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
$addToSet
Cursor
db.<col>.help([commandName]);
date
12. Returns help information for a command.
db.commandHelp("commandName")
db.help([commandName]);
64-bit floating point numbers
Cursor
13. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
use <database name>
batch insert
$nin
14. Returns all the documents matching the optional properties.
undefined
32-Bit Integer
db.<collection>.find([properties]);
$gt
15. Clone the current database (implied by 'db') from another host.
key.index
32-Bit Integer
db.cloneDatabase(fromhost)
date
16. Returns all the documents matching the optional properties.
$mod
$rename
db.<collection>.find([properties]);
binary data
17. command to start the mongodb process.
mongod
Update Modifiers
$lt
64-bit floating point numbers
18. In BSON - represents the largest possible value.
object id
$ne
maximum value
Cursor
19. Array specific conditional used to select based on the length or set-size of an array field value.
$size
mongod
db.<col>.help([commandName]);
db.commandHelp("commandName")
20. Returns the size of a document after it is converted to BSON from the JSON-like original.
mongod
Object.bsonsize({document});
use <database name>
db.<collection>.find([properties]);
21. Adds a document to a collection.
db.<collection>.insert({document});
$lt
maximum value
$gt
22. 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 } }
db.cloneDatabase(fromhost)
$pop
$size
db.commandHelp("commandName")
23. Used to represent both a null value and a nonexistent field.
$in
db.cloneDatabase(fromhost)
null
object id
24. ...
minimum value
$unset
batch insert
boolean
25. Deletes documents from the collection based on the selector.
$gt
$pushAll
db.getLastError()
db.<col>.remove({selector});
26. Operator allowing the partial specification of fields in an embedded document in an array.
$inc
db.<collection>.insert({document});
$elemMatch
$pop
27. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pull
help
32-Bit Integer
$pullAll
28. Command to get help docs on a specific command at the db level.
binary data
$all
$pushAll
db.help([commandName]);
29. Syntax used for selectors to be specific to a certain element position within an array.
$in
$inc
db.help([commandName]);
key.index
30. Query conditional allowing the selector to choose between more than one optional criteria.
$gte
$or
db.getLastError()
db.commandHelp("commandName")
31. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
db.<collection>.find([properties]);
$lt
embedded document
$slice
32. Updates all matching documents, not just the first, that match the selector.
Multi-updates
db.<collection>.find([properties]);
Cursor
db.<collection>.find([properties]);
33. 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 } }
$addToSet
$pushAll
$where
$rename
34. command to start the mongodb process.
db.runCommand({fsync:1,lock:1,async:1})
$set
$addToSet
mongod
35. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
db.<collection>.insert({document});
document
Upsert
$gte
36. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
Cursor
$lte
use <database name>
batch insert
37. Operator allowing the execution of arbitrary javascript as part of the selector.
db.<collection>.find([properties]);
$where
db.commandHelp("commandName")
Object.bsonsize({document});
38. Update a document in the collection.
array
mongod
db.<col>.remove({selector});
db.<col>.update({selector},{document});
39. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
db.commandHelp("commandName")
db.myCollection.ensureIndex({keypattern},[{options}])
db.help([commandName]);
db.getLastError()
40. A document contained by a parent document. The embedded document is a value of a key in the parent document.
code
embedded document
string
mongod
41. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
$ne
string
db.cloneDatabase(fromhost)
document
42. changes the database on which you are working.
minimum value
Upsert
use <database name>
$pushAll
43. Javascript code. Documents can contain code as values.
$size
show collections
code
db.getLastError()
44. Standard binary data type.
64-Bit Integer
mongod
undefined
boolean
45. Binary-encoded serialization of mongo documents.
db.cloneDatabase(fromhost)
db.<collection>.insert({document});
mongo
BSON
46. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
object id
db.getLastError()
64-Bit Integer
$mod
47. 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.myCollection.ensureIndex({keypattern},[{options}])
null
$not
$all
48. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.getLastError()
document
db.runCommand({fsync:1,lock:1,async:1})
$set
49. 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
$rename
db.<collection>.find([properties]);
string
50. 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 ] } } }
$addToSet
regular expression
array
use <database name>