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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. In BSON - represents the largest possible value.
db.<collection>.insert({document});
db.<col>.help([commandName]);
db.<collection>.find([properties]);
maximum value
2. Command to get help docs on a specific command at the db level.
$in
document
$or
db.help([commandName]);
3. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
mongod
help
$unset
$gt
4. changes the database on which you are working.
use <database name>
binary data
db.commandHelp("commandName")
$ne
5. Contains query conditional used to check if a value contains the field value.
$unset
$in
object id
batch insert
6. Clone the current database (implied by 'db') from another host.
$pullAll
$pushAll
db.cloneDatabase(fromhost)
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
7. The standard number representation in the javascript shell.
$lt
key.index
64-bit floating point numbers
code
8. Deletes a given field. ex: { $unset : { field : 1} }
$lte
date
$gt
$unset
9. Creates an index on property(s). Options can describe the type of sorting, uniqueness, etc.
mongo
$unset
mongod
db.myCollection.ensureIndex({keypattern},[{options}])
10. Returns help information for a command.
db.commandHelp("commandName")
BSON
$mod
boolean
11. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
$gte
db.commandHelp("commandName")
mongod
batch insert
12. Set or list of values.
db.<collection>.find([properties]);
$pull
array
$rename
13. Used to describe a variable as not having been initialized.
string
$ne
$lte
undefined
14. Standard javascript regular expressions. These can be stored in documents
regular expression
db.<collection>.findOne([properties]);
db.help([commandName]);
boolean
15. 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>.insert({document});
key.index
$not
$pushAll
16. Returns all the documents matching the optional properties.
$ne
mongod
db.<collection>.find([properties]);
$nin
17. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
$set
mongod
db.<collection>.find([properties]);
32-Bit Integer
18. Command to list commands and descriptions of those commands in the context of the database.
help
mongod
Upsert
document
19. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
db.<collection>.insert({document});
boolean
Cursor
string
20. Standard binary data type.
boolean
db.commandHelp("commandName")
db.<collection>.findOne([properties]);
key.index
21. A document contained by a parent document. The embedded document is a value of a key in the parent document.
embedded document
$addToSet
db.<collection>.insert({document});
date
22. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
document
db.myCollection.ensureIndex({keypattern},[{options}])
help
23. Javascript code. Documents can contain code as values.
code
db.<collection>.insert({document});
db.<collection>.find([properties]);
$mod
24. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pull
Cursor
db.runCommand({fsync:1,lock:1,async:1})
embedded document
25. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
$pullAll
db.cloneDatabase(fromhost)
batch insert
undefined
26. Update modifier used to increment a value. ex: {"$inc":{"counter":2}}
$set
$inc
db.getLastError()
db.<col>.remove({selector});
27. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
regular expression
$push
64-Bit Integer
object id
28. 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.help([commandName]);
$pop
db.<collection>.findOne([properties]);
$not
29. Update modifier that set the value of a key and if the key does not exist, it will create the key. ex: db.<col>.update({selector},{"$set":{"someKey":"someValue"}});
$elemMatch
$mod
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$set
30. set of UTF-8 characters.
$size
64-bit floating point numbers
string
maximum value
31. Returns help information for a command.
db.commandHelp("commandName")
Update Modifiers
Multi-updates
object id
32. Syntax used for selectors to be specific to a certain element position within an array.
minimum value
32-Bit Integer
$not
key.index
33. Array specific conditional used to select based on the length or set-size of an array field value.
Cursor
64-bit floating point numbers
BSON
$size
34. 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.
$in
$mod
db.runCommand({fsync:1,lock:1,async:1})
$pull
35. Less than query conditional. ex: db.<col>.find({numVal: {$lt:3}});
$pop
date
$size
$lt
36. Lists all the collections in the database in use.
array
$push
show collections
db.cloneDatabase(fromhost)
37. Stored as milliseconds since the epoch.
db.<col>.remove({selector});
$pull
db.runCommand({fsync:1,lock:1,async:1})
date
38. 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
$addToSet
Update Modifiers
mongo
39. 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 } }
$where
Multi-updates
$push
db.myCollection.ensureIndex({keypattern},[{options}])
40. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
db.<col>.remove({selector});
boolean
db.getLastError()
use <database name>
41. Data structure used to store all other data in mongo databases.
document
db.getLastError()
binary data
$or
42. Not equal query conditional. ex: db.<col>.find({numVal: {$ne:3}});
db.<col>.remove({selector});
db.<collection>.insert({document});
$ne
use <database name>
43. Command to get help docs on a specific command at the collection level.
use <database name>
object id
db.<col>.help([commandName]);
null
44. 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.
object id
db.getLastError()
$all
help
45. Adds a document to a collection.
maximum value
use <database name>
minimum value
db.<collection>.insert({document});
46. 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.runCommand({fsync:1,lock:1,async:1})
db.getLastError()
$unset
$pop
47. 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.
BSON
$size
help
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
48. command to start the mongodb process.
binary data
show collections
mongod
db.<collection>.insert({document});
49. Positional operator that holds the position of the first matched array item in the query. Used to find an array member and then manipulate it. ex: {$inc:{'comments.$.votes':1}} where comments looks like: "comments" : [ { "by" : "joe", "votes" : 3 },
help
batch insert
Cursor
$
50. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
$nin
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
db.cloneDatabase(fromhost)
db.getLastError()