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

Question : By doing data nesting in Cassandra, we can support a partition per query access pattern

1. True
2. False

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Explanation: Cassandra, like many other NOSQL databases, stored data is highly denormalized. The denormalized data
often manifests itself in the form of a nested object e.g., deformalizing one to many relations.




Question : What all are the advantages of Mapping Rule if applied correctly in Cassandra Data Model?
A. ensure that logical data model is correct
B. each query has a corresponding table
C. tables are designed to allow query to execute properly
D. table returns data in correct order


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

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Explanation: : There are five mapping rules that guide a query-driven transition from a
conceptual data model to a logical data model. Which helps in
ensure that logical data model is correct
each query has a corresponding table
tables are designed to allow query to execute properly
table returns data in correct order





Question : As per mapping rule (Entity and Relationship) what is true ?

1. Entity and relationship types map to tables

2. Entities and relationships map to table rows

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table columns at
the logical level.

4. 1 and 3

5. 1,2 and 3


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Explanation: MR1 (Entities and Relationships). Entity and relationship
types map to tables, while entities and relationships map to table
rows. Attribute types that describe entities and relationships
at the conceptual level must be preserved as table columns at
the logical level. Violation of this rule may lead to data loss.

Related Questions

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Question : You have been given below table definition

CREATE TABLE HADOOEXAM(

COURSE_TITLE text,
COURSE_ADDED_YEAR int,
COURSE_ADDED_DATE timestamp,
COURSE_DETAIL text,
USER_ID UUID,
COURSE_ID TIMEUUID,
PRIMARY KEY ((COURSE_TITLE), COURSE_ADDED_YEAR)));

What is the advantage of having PRIMARY KEY defined with this syntax ((COURSE_TITLE), COURSE_ADDED_YEAR))) ?

1. COURSE_ADDED_YEAR column Provide uniqueness within the partition as well as ordering criteria

2. COURSE_ADDED_YEAR column Groups related data on a single node

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4. COURSE_ADDED_YEAR column Creates clusters within the rack



Question : . You have been given below table definition

CREATE TABLE HADOOEXAM (

COURSE_TITLE text,
COURSE_ADDED_YEAR int,
COURSE_ADDED_DATE timestamp,
COURSE_DETAIL text,
USER_ID UUID,
COURSE_ID TIMEUUID,
PRIMARY KEY ((COURSE_TITLE), COURSE_ADDED_YEAR)));

What is the relation between COURSE_TITLE and COURSE_ADDED_YEAR in this definition?

1. Behavior for COURSE_TITLE and COURSE_ADDED_YEAR are the same.

2. COURSE_ADDED_YEAR column hash to a partition key

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criteria

4. COURSE_ADDED_YEAR column determine grouping criteria whereas COURSE_TITLE key determine ordering criteria



Question : You have been given below table definition

CREATE TABLE HADOOEXAM(

COURSE_TITLE text,
COURSE_ADDED_YEAR int,
COURSE_ADDED_DATE timestamp,
COURSE_DETAIL text,
USER_ID UUID,
COURSE_ID TIMEUUID,
PRIMARY KEY ((COURSE_TITLE), COURSE_ADDED_YEAR)));

How does Cassandra will order this table columns?

1. COURSE_TITLE, COURSE_ADDED_YEAR, COURSE_ADDED_DATE , COURSE_DETAIL , COURSE_ID , USER_ID

2. COURSE_ADDED_YEAR, COURSE_TITLE, COURSE_ADDED_DATE , COURSE_DETAIL , COURSE_ID , USER_ID

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4. COURSE_TITLE, COURSE_ADDED_YEAR, COURSE_ADDED_DATE , COURSE_DETAIL , USER_ID, COURSE_ID



Question : You have been given metadata for creating Cassandra table.

Category text
Created_year int
course_id uuid
published_date timestamp
course_detail text
course_title text
user_id uuid

And you have created table as below

CREATE TABLE HADOOPEXAM (
Category text,
Created_year int,
published_date timestamp,
course_title text,
course_detail text,
user_id uuid,
course_id uuid,
PRIMARY KEY ((course_id))
);

What do you see in above table creation definition assuming combination of these three columns course_id,Category,Created_year
to be unique across all data.


1. It is a good design of table, it can avoid the upserts.

2. It is a good design of table, and you can easily do the range query on Created_year column.

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4. Its not a good or bad design. Itas based on requirement.



Question : You have been given below metadata for creating Cassandra table.

Category text
Created_year int
course_id uuid
published_date timestamp
course_detail text
user_id uuid

In this assuming combination of these three columns course_id,Category,Created_year to be unique across all data.
Now you need to design a table where allow users to query on Category and possible created_year ranges while avoiding upserts
on import. You must also return your results in descending order of created_year.

1.



2.


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4.




Question : You have wrongly loaded all the data in Cassandra table and want to delete all the rows from that table. Which of
the following will help you to do this?

1. DROP

2. TRUNCATE

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4. ERASE