Premium

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



Question : Select correct statement for Cassandra database, w.r.t. RDBMS
A. Cassandra is designed as a distributed database with peer-to-peer communication.
B. As a best practice, queries should involve at least two table.
C. Data should be de-normalized.
D. client-side joins can be used in applications, after data fetch from Cassandra.

: Select correct statement for Cassandra database, w.r.t. RDBMS
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,C,D

Correct Answer : 3
Explanation: Cassandra is designed from the ground up as a distributed database with peer-to-peer communication.
As a best practice, queries should be one per table. Data is denormalized to make this possible.
For this reason, the concept of JOINs between tables does not exist, although client-side joins can be used in applications.





Question : Select correct statement which applies for CQL.
A. CQL and SQL share the same abstract idea of a table constructed of columns and rows.
B. Cassandra emphasizes denormalization through CQL features like collections and clustering specified at the schema level
C. Cassandra does not support joins.
D. Cassandra does not support subqueries.

: Select correct statement which applies for CQL.
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,C,D

Correct Answer : 4
Explanation: Cassandra Query Language (CQL) is the primary interface into the Cassandra DBMS. Using CQL is
similar to using SQL (Structured Query Language). CQL and SQL share the same abstract idea of a table constructed
of columns and rows. The main difference from SQL is that Cassandra does not support joins or subqueries. Instead, Cassandra
emphasizes denormalization through CQL features like collections and clustering specified at the schema level.

CQL is the recommended way to interact with Cassandra. Performance and the simplicity of reading and using CQL is
an advantage of modern Cassandra over older Cassandra APIs.





Question : Which all are possible using cqlsh
A. you can create keyspaces
B. you can create tables
C. you can insert and query tables

: Which all are possible using cqlsh
1. A,B
2. B,C
3. A,C
4. A,B,C

Correct Answer : 4
Explanation: The most basic way to interact with Cassandra is using the CQL shell, cqlsh. Using cqlsh,
you can create keyspaces and tables,
insert and query tables, plus much more. If you prefer a graphical tool, you can use DevCenter. For production,
DataStax supplies a number of
drivers in various programming languages, so that CQL statements can be passed from client to cluster and back.



Related Questions

Question : Map the below, components
A. Node
B. Data center
C. Cluster

1. It can span Physical locations
2. Where you store your data. It is the basic infrastructure component of Cassandra
3. A collection of related machines and can be physical as well as virtual

 : Map the below, components
1. A-2 , B-3 , C-1

2. A-1 , B-2 , C-3
3. A-1 , B-3 , C-2
4. A-3 , B-1 , C-2


Question : Map the followings
A. Commit log
B. SSTable
C. CQL Table

1. Consists of columns and has a primary key
2. All data is written first to this for durability.
3. Maintained for each Cassandra table

 : Map the followings
1. A-1 B-2 C-3

2. A-3 B-2 C-1
3. A-1 B-3 C-2
4. A-2 B-3 C-1


Question : Select correct statements, with regards to Gossip protocol.
A. Using Gossip protocol nodes periodically exchange state information about themselves and about other nodes they know about.
B. The gossip process runs every 5 seconds and exchanges state messages with as many other nodes in the cluster as possible.
C. The nodes exchange information about themselves and about the other nodes that they have gossiped about,
so all nodes quickly learn about all other nodes in the cluster.
D. A gossip message has a version associated with it

 : Select correct statements, with regards to Gossip protocol.
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,C,D


Question : Select all correct statements which applies to seed nodes
A. Use the multiple list of seed nodes in a cluster, so all nodes quickly learn about all other nodes in the cluster
B. The seed node designation has no purpose other than bootstrapping the gossip process for new nodes joining the cluster
C. Seed nodes are not a single point of failure
D. Seed nodes are a single point of failure

 : Select all correct statements which applies to seed nodes
1. A,B
2. B,C
3. C,D
4. A,D
5. B,D


Question : Select all correct statements which applies to seed nodes
A. In multiple data-center clusters, the seed list should include at least one node from each data center (replication group).
B. More than a single seed node per data center is recommended for fault tolerance
C. Making every node a seed node is recommended for fault tolerance
D. It is recommended to use a small seed list (approximately three nodes per data center).

 : Select all correct statements which applies to seed nodes
1. A,B,C
2. B,C,D
3. A,C,D
4. A,B,D


Question : In Cassandra database, which of the following help us to put new row on a particular node in a cluster.


 : In Cassandra database, which of the following help us to put new row on a particular node in a cluster.
1. Hashing

2. Partitioner

3. Gossip protocol

4. Grouping

5. Timestamps