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

Question : Which of the following aggregation functions are supported by Cassandra as of now ?


1. SUM

2. MAX

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4. COUNT

5. AVG


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Explanation: Cassandra currently support only Count aggregation functions.




Question : Which of the following statement is correct for Counter data type

1. They are always 100% accurate

2. You can do add, subtract, increment and decrement current value

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4. 1 and 3

5. 2 and 3


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Explanation: A counter is a special column used to store a number that is changed in increments. For example, you
might use a counter column to count the number of times a page is viewed.

Define a counter in a dedicated table only and use the counter data type. You cannot index, delete, or re-add a counter
column. All non-counter columns in the table must be defined as part of the primary key.

To load data into a counter column, or to increase or decrease the value of the counter, use the UPDATE command. Cassandra
rejects USING TIMESTAMP or USING TTL in the command to update a counter column.





Question : You have been given a Cassandra cluster (Ring) with nodes, spread across two availability zones (AWS : amazon
webservice) and new KeySpace created
by Admin named AcmeKeySpace with Replication factor 3. Select correct statement.
A. Whatever data updates are done can not be replicated to another availability zone.
B. Whatever data inserts are done can not be replicated to another availability zone.
C. Whatever data updates are done , automatically replicated to another availability zone.
D. Whatever data inserts are done , automatically replicated to another availability zone.


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

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Explanation: Built-in and customizable replication: Cassandra also provides built-in and customizable
replication, which stores redundant copies of data across nodes that participate in a Cassandra ring.
This means that if any node in a cluster goes down, one or more copies of that nodeas data is available on other machines in
the cluster.
Replication can be configured to work across one data center, many data centers, and multiple cloud availability zones.

Related Questions

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

1. True
2. False


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


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



Question : You have a query with the where clause and all the predicates use equality operator like =, != etc.
What is correct in this scenario, with regards to mapping rule?

1. search attributes, which are used in a query predicate, map to the prefix columns of a table primary key.

2. Such columns must include all partition key columns and, optionally, one or more clustering key columns.

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4. 1 and 2

5. 2 and 3



Question : Which of the following is correct with regards to mapping rule Inequality Search Attributes

1. An inequality search attribute, which is used in a query predicate, maps to a table clustering key column.

2. In the primary key definition, a column that participates in inequality search must follow columns that
participate in equality search.

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4. 1 and 2

5. 1,2 and 3



Question : You have a query, where you have to order by the data by a particular column. In this case you have to use this
column with the clustering key?

1. True
2. False