DataStax Cassandra Developer Certification Certification Questions and Answer (Dumps and Practice Questions)

Question : When multiple occurrences of data match a condition in a WHERE clause, Cassandra selects the most-frequent
occurrence of a condition for processing first for efficiency.



1. True
2. False

Correct Answer : Get Lastest Questions and Answer :
Explanation: When multiple occurrences of data match a condition in a WHERE clause, Cassandra selects the
least-frequent occurrence of a condition for processing first for efficiency. For example, suppose data for author
"HadoopExam" and "Book Name :CASSANDRA" were inserted into the books table. Cassandra queries on the category name first if
there are fewer categories named "NOSQL" than there are books called "Cassandra" in the database.

SELECT * FROM Books WHERE category = 'NoSQL' AND title = 'Cassandra' ALLOW FILTERING ;

When you attempt a potentially expensive query, such as searching a range of rows, Cassandra requires the ALLOW FILTERING
directive.





Question : You have been given two separate csv file as below.

course.csv : with following sample data

62c36092-82a1-3a00-93d1-46196ee77204, cassandra,{nosql,bigdata},

subscriber.csv (All the subscriber of the training course, it is possible a single company can have multiple user)
62c36092-82a1-3a00-93d1-46196ee77204, {hadoopexam@gmail.com, admin@hadoopexam.com} , Amit Jain

Which of the following is correct way to accommodate these data in Cassandra table?

A.
CREATE TABLE HADOOPEXAM {
course_id timeuuid,
title text,
Category set
}

CREATE TYPE SUBSCRIBER_TYPE {
course_id timeuuid,
emails set,
name text
}

ALTER TABLE HADOOPEXAM add SUBSCRIBER frozen;

B.

CREATE TYPE SUBSCRIBER_TYPE {
course_id timeuuid,
emails set,
name text
}

CREATE TABLE HADOOPEXAM {
course_id timeuuid,
title text,
Category set,
SUBSCRIBER SUBSCRIBER_TYPE
}

C.
CREATE TABLE SUBSCRIBER_TYPE {
course_id timeuuid,
emails set,
name text
}

CREATE TABLE HADOOPEXAM {
course_id timeuuid,
title text,
Category set,
SUBSCRIBER SUBSCRIBER_TYPE
}

D. CREATE TABLE SUBSCRIBER_TYPE {
course_id timeuuid,
emails map,
name text
}

CREATE TABLE HADOOPEXAM {
course_id timeuuid,
title text,
Category map,
SUBSCRIBER SUBSCRIBER_TYPE
}


1. A,B
2. B,C
3. Access Mostly Uused Products by 50000+ Subscribers
4. A,D
5. B,D

Correct Answer : Get Lastest Questions and Answer :
Explanation: Both option 1 and 2 are correct. As you know, for unique text values we can use set
type. We can use map type only if there are keys and values.

We can first create table and alter later on to add new column.
or we can define table with have all the columns at first.

To create custom type, we have to use syntax as below.

CREATE TYPE SUBSCRIBER_TYPE {
course_id timeuuid,
emails set,
name text
}





Question : Cassandra counters are always % accurate.

1. True
2. False

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Explanation:

Related Questions

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Question : Which of the following are important components to deciding, on which node a replica needs to be kept.

A. Snitches
B. replication strategy
C. replication factor
D. Partitioner
E. Gossip


1. A,B
2. B,C
3. C,D
4. D,E
5. A,E


Question : You have multi-datacenter cluster and a keyspace with, replication factor as . Which of the following will help
you to determine best replica for reading.



1. Snitches

2. replication strategy

3. replication factor

4. Partitioner

5. All replicas are equal and can be read from any node. And no need to find best replica to read.



Question : You must configure a snitch when you create



1. Keyspace

2. Cluster

3. Table

4. Column Family



Question : Which all of the below can be configured in cassandra.yaml configuration file
A. Caching parameters for tables
B. Properties for tuning and resource utilization
C. Timeout settings
D. Client connections
E. Backups
F. Security


1. A,B,C
2. C,D,E
3. D,E,F
4. A,B,E
5. A,B,C,D,E,F


Question : You can set storage configuration attributes on a
A. per-keyspace basis
B. per-table basis
C. per column-family basis
D. per data-center basis


1. A,B
2. B,C
3. C,D
4. A,D
5. B,D


Question : _______ allows distribution of data across a cluster to minimize reorganization when nodes are added or removed
and it partitions data based on the __________



1. Consistent hashing, partition key

2. Random hashing, primary key

3. Consistent hashing, hash key

4. Replication, Replication strategy