C100DBA Online Practice Questions and Answers
What tool do you use to see if you have a problem in the consumption of disk I / 0?
A. Mongoperf
Which of the documents below will be retrieved by the following query? Assume the documents are stored in a collection called "sample". Check all that apply.
db.sample.find( { "$or" : [ { "a" : { "$in" : [ 3, 10] > }, { "b" : { "$lt" : 2 > > ] > )
A. {''__id" :3, "a": 4, "c" :0, "b" :14}
B. {''_Jd" :7, "a": 8, "c" :1, "b" :7}
C. {".Jd" :6, "a": 1, "c" :1, "b" :5}
D. { ''\Jd" :9, "a": 17, "c": 1, "b": 1}
E. { \Jd" :10,"a": 3, "c": 1, "b": 1}
F. {".Jd" :: 2, "a": 2, "c" :: 0, "b": 1}
G. {".Jd" :: 4, "a": 5, "c" :: 0, "b": 17}
H. {".Jd" :: 1, "a": 0, "c" :: 0, "b": 2}
I. {".Jd" :: 5, "a": 3, "c" :: 0, "b": 12}
J. {".Jd" :: 8, "a": 11, "c": 1, "b": 0}
Which of the following statements are true about the $match pipeline operator? Check all that apply.
A. You should use it early as possible in the pipeline
B. It can be used as many time as needed.
C. It has a sintax similar to findQ commands.
Which of the following command is used to get all the indexes on a collection?
A. db.collection.showIndexes()
B. db.collection.findlndexes()
C. db.showIndexes()
D. db.collection.getlndexesQ
Which of the following aggregate commands in MongoDB uses a pipeline approach with the goals of improving the aggregation performance?
A. mapReduce
B. group
C. aggregate
D. All of the above
You perform the following operation in the shell: db.foo.insert( { } ); What gets inserted?
A. A document will be inserted with the same _id as the last document inserted
B. A document that matches the collection's existing schema, but with null fields
C. A document with an _id assigned to be an Objectld
D. An empty document
E. No document will be inserted; an error will be raised
What is the maximum size of Index Key Limit and Number of Indexes per collection?
A. 1024 bytes and 64 indexes
B. 12 mega bytes and 64 indexes
C. 64 bytes and 1024 indexes
D. 1024 bytes and unlimited indexes
Which command is used to determine storage capacity of specific database?
A. mongotop
B. dbstats
C. mongostat
D. constats
Which of the following does MongoDB use to provide High Availability and fault tolerance?
A. Sharding
B. Indexing
C. Replication
D. Write Concern