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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. command to start the mongo shell.
mongo
Multi-updates
$not
$rename
2. Returns one document matching the optional properties.
db.<collection>.findOne([properties]);
$unset
db.commandHelp("commandName")
object id
3. 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 } }
$push
db.runCommand({fsync:1,lock:1,async:1})
$elemMatch
$pullAll
4. Clone the current database (implied by 'db') from another host.
db.cloneDatabase(fromhost)
$pull
$gte
32-Bit Integer
5. Returns information about the last operation. Not necessarily error data - the return can contain things like number of records updated.
$elemMatch
$pop
db.getLastError()
mongo
6. 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.
mongo
$or
32-Bit Integer
Update Modifiers
7. Removes all occurrences of each value in the passed in array from the field. ex: { $pullAll : { field : value_array } }
object id
mongo
BSON
$pullAll
8. Does not contain query conditional used to select documents with the field that is not in the selector list of values.
32-Bit Integer
$nin
$where
db.help([commandName]);
9. Command to get help docs on a specific command at the db level.
$elemMatch
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
mongo
db.help([commandName]);
10. Operator allowing the execution of arbitrary javascript as part of the selector.
$mod
$where
$
db.getLastError()
11. 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 } }
mongo
use <database name>
$pushAll
db.<collection>.find([properties]);
12. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
BSON
array
db.runCommand({fsync:1,lock:1,async:1})
13. Positional operator that holds the position of the first matched array item in the query. Used to find an array member and then manipulate it. ex: {$inc:{'comments.$.votes':1}} where comments looks like: "comments" : [ { "by" : "joe", "votes" : 3 },
batch insert
$
$set
64-bit floating point numbers
14. The standard number representation in the javascript shell.
64-bit floating point numbers
null
db.myCollection.ensureIndex({keypattern},[{options}])
db.<collection>.insert({document});
15. command to start the mongo shell.
binary data
mongo
Multi-updates
db.<col>.update({selector},{document});
16. 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 ] } } }
$pushAll
$not
$size
$addToSet
17. Returns help information for a command.
null
db.commandHelp("commandName")
db.<col>.remove({selector});
$inc
18. Returns the size of a document after it is converted to BSON from the JSON-like original.
boolean
Object.bsonsize({document});
$size
db.<col>.update({selector},{document});
19. Operator used in the second argument of the find() call to specify which slice of an array to return for an array field.
$slice
minimum value
batch insert
code
20. Command to get help docs on a specific command at the collection level.
show collections
db.<col>.help([commandName]);
db.<collection>.insert({document});
64-bit floating point numbers
21. Less than or equal query conditional. ex: db.<col>.find({numVal: {$lte:3}});
$nin
db.help([commandName]);
$mod
$lte
22. Update call that inserts a new document if no update match is found. Allows the same code to be used for inserts as well as updates.
$where
$not
Upsert
db.commandHelp("commandName")
23. Not supported by the javascript shell and are converted to 64-bit floating point numbers.
64-Bit Integer
$gt
db.<collection>.find([properties]);
key.index
24. Adds a document to a collection.
db.<collection>.insert({document});
$push
db.getLastError()
$where
25. Greater than or equal query conditional. ex: db.<col>.find({numVal: {$gte:3}});
$gt
$gte
help
mongod
26. Contains query conditional used to check if a value contains the field value.
$in
$set
$addToSet
BSON
27. Removes all occurrences of a value from a field. ex: { $pull : { field : _value } }
$pull
$or
db.cloneDatabase(fromhost)
64-Bit Integer
28. Used to describe a variable as not having been initialized.
undefined
null
$inc
$set
29. changes the database on which you are working.
key.index
use <database name>
64-bit floating point numbers
db.getLastError()
30. Stored as milliseconds since the epoch.
db.<collection>.insert({document});
date
$all
show collections
31. Command to list commands and descriptions of those commands in the context of the database.
help
$push
db.<col>.remove({selector});
$set
32. Javascript code. Documents can contain code as values.
$gt
$addToSet
code
$not
33. command to start the mongodb process.
Cursor
mongod
32-Bit Integer
minimum value
34. Update a document in the collection.
db.<col>.update({selector},{document});
help
document
undefined
35. Used to represent both a null value and a nonexistent field.
null
db.<collection>.find([properties]);
$ne
$all
36. Renames a field from the one indicated to the new field name. ex: { $rename : { old_field_name : new_field_name } }
db.cloneDatabase(fromhost)
db.<col>.update({selector},{document});
$rename
db.runCommand({fsync:1,lock:1,async:1})
37. Unique 12-byte ID for documents.
$unset
db.runCommand({fsync:1,lock:1,async:1})
db.<col>.update({selector},{document});
object id
38. 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.
$lt
$addToSet
string
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
39. Standard javascript regular expressions. These can be stored in documents
regular expression
$lt
embedded document
db.<collection>.findOne([properties]);
40. 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.
$not
$mod
db.copyDatabase(frmDBName, toDBName, [frmHostName], [user], [pwd]);
$where
41. 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.<col>.update({selector},{document});
32-Bit Integer
$pop
null
42. A document contained by a parent document. The embedded document is a value of a key in the parent document.
$push
embedded document
show collections
batch insert
43. The local variable representation of a query. Uniquely - the cursor does not hold the results but instead access to the results.
$elemMatch
object id
Cursor
db.<col>.remove({selector});
44. Query conditional allowing the selector to choose between more than one optional criteria.
32-Bit Integer
$ne
$or
db.<collection>.find([properties]);
45. Returns all the documents matching the optional properties.
db.<collection>.find([properties]);
null
use <database name>
maximum value
46. Greater than query conditional. ex: db.<col>.find({numVal: {$gt:3}});
$gt
Update Modifiers
32-Bit Integer
$elemMatch
47. In BSON - represents the smallest possible value.
$unset
Object.bsonsize({document});
minimum value
$gt
48. Meta query conditional used to negate the selector.
null
db.myCollection.ensureIndex({keypattern},[{options}])
db.<collection>.insert({document});
$not
49. String of arbitrary bytes.
$lte
$nin
$inc
binary data
50. 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.runCommand({fsync:1,lock:1,async:1})
$all
string
$nin