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

Question : Cassandra stores an entire row of data on a node by partition key. If you have too much data in a partition and
want to spread the data over multiple nodes, use a ________________

1. Secondary Index

2. composite partition key.

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4. Single Column Primary key

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Explanation: Cassandra stores an entire row of data on a node by partition key. If you have too much data in a
partition and want to spread the data over multiple nodes, use a composite partition key.

Question : You have already defined a table named HADOOPEXAM, now you want to add unique collection of email address for
each primary key, which of the following is correct statement

1. ALTER TABLE HADOOPEXAM ADD emails set;

2. ALTER TABLE HADOOPEXAM ADD emails list;

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4. ALTER TABLE HADOOPEXAM ADD email1 text, email2 text, email3 text;

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Explanation: CQL contains these collection types:

set (Unique Values)
list (Duplicate values can be possible)
map (Key value pair)
In a relational database, to allow users to have multiple email addresses, you create an email_addresses table having a
many-to-one (joined) relationship to a useras table. CQL handles the classic multiple email addresses use case, and other use
cases, by defining columns as collections. Using the set collection type to solve the multiple email addresses problem is
convenient and intuitive.

Question : . You have defined a table as below

CREATE TABLE TRINING_COURSE (
id uuid,
course_sequence int,
course_id uuid,
title text,
category text,
trainer text,
PRIMARY KEY (id, course_sequence ) );

ALTER TABLE TRINING_COURSE ADD emails set;

Which of the following is correct CQL to add new emailid for a training_course

1. ADD VALUE TO TRINING_COURSE IN emails = emails + {'hadoopexam@gmail.com'}
WHERE id = 62c36092-82a1-3a00-93d1-46196ee77204 AND course_sequence = 2;

2. UPDATE TRINING_COURSE SET emails = emails + {'hadoopexam@gmail.com'}
WHERE id = 62c36092-82a1-3a00-93d1-46196ee77204 AND course_sequence = 2;

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WHERE id = 62c36092-82a1-3a00-93d1-46196ee77204 AND course_sequence = 2;

4. UPDATE TRINING_COURSE SET emails = {emails, {'hadoopexam@gmail.com'}}
WHERE id = 62c36092-82a1-3a00-93d1-46196ee77204 AND course_sequence = 2;

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Explanation: Each element of a set, list, or map is internally stored as one Cassandra column. To update a set,
use the UPDATE command and the addition (+) operator to add an element or the subtraction (-) operator to remove an element.

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

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