Cassandra Tutorial

What is Cassandra?

• A distributed database from Apache which is profoundly scalable and Cassandra is built to manage vast volumes of structured data. Cassandra gives excellent availability without any single failure.
• Cassandra is a database with NoSQL given by Apache.
• Within Cassandra the proven fault-tolerance and linear scalability upon the infrastructure of the cloud or the hardware of commodity which makes Cassandra the perfect and best platform for critical data, Cassandra gives more economical latency for users and assistance for replicating over various datacenters. 

Characteristics of Cassandra:

• Within Cassandra, the data stored as tables.
• Every table of Cassandra contains a primary key.
• Cassandra contains a key-value database.
• There is a limited SQL interface within Cassandra.
• Cassandra is extremely scalable, which helps us to combine more hardware to connect with more extra clients and added data as per the necessity.    
• Cassandra maintains every potential data forms like structured data, semi-structured data, and unstructured data. It promotes us to make modifications to our data structures according to our requirements.
• Data administration within Cassandra is effortless because Cassandra gives the versatility to distribute data wherever you require by replicating data over various data stations.
• Cassandra holds ACID characteristics like Atomicity, Consistency, Isolation, and Durability.  

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Simple Cassandra syntax:

Select student, value

From college

Where student_id=" 123".

Order by student

Advantages of Cassandra:

• Large volumes of data stored as quickly as possible.
• Cassandra is Apache open-source design, and this indicates Cassandra is accessible for free, True, we can download the app and utilize the way you require. In particular, it is open-source cosmos has provided source to a large Cassandra community wherever similar minded people administer their opinions, queries, instructions associated with Big Data.
• Cassandra follows a peer-to-peer structure, preferably of slave-master design. Therefore, there is not even a single failure within Cassandra. 
• Probably the most significant bit of leeway of utilizing Cassandra is its flexible adaptability. Cassandra group can be handily scaled-up or downsized. Curiously, any number of hubs can be included or erased in Cassandra bunch absent a lot of aggravation. You don't need to restart the group or change questions related to Cassandra's application while scaling up or down.

History of Cassandra:

Cassandra first developed for the Facebook inbox search feature, Facebook open-sourced Cassandra in July 2008, in march 2009 Cassandra accepted by apache Incubator, Cassandra has become the high-level project for Apache since 2010. Apache Cassandra 3.2.1 is the latest version.

Applications of Cassandra:

• Cassandra is a comprehensive database that can manage a massive volume of data. Implies it is favored for the businesses which present Mobile phones and messaging assistance. These corporations hold a tremendous quantity of data, so Cassandra is most suitable for them.
• Cassandra can manage the high-speed data, so that remains a prominent database to the applications wherever data is occurring at extremely high velocity of various sensors or devices.
• Cassandra is a comprehensive database for various online organizations and providers of social media for review and guidance to their clients.
• Numerous retailers utilize Cassandra for enduring purchasing cart security and quick product description input plus output.

NoSQL database Vs Relational Database

Objectives of the NoSQL database:

The three main goals of Cassandra are

• Cassandra is simple to learn
• High availability
• Horizontal scaling

Cassandra CQL API:

There are a few different APIs in Cassandra but let us discuss Cassandra CQL API as it is the most crucial APIs of Cassandra. In Cassandra, the principle storage unit is a table. At the point when the client characterizes a counter for the database, Cassandra utilizes CQL API. As indicated by Cassandra Query Language API, a table is essential, a lot of allotments. These segments are necessarily rows and columns. The sections are fields that connote cell subtleties. The column means the number of passages in a table. The table may contain a single or different number of the two rows and columns. In a table, there is a segment key. The parcel key is essentially an exceptional identifier of a segment and might be straightforward or composite. Besides, the section recognizes cells and might be ordinary or grouping. At the point when a client makes a table, a column set to the essential key. The primary key is a particular segment or field, which is the first identifier in a table.  

Cassandra Interview Questions

Cassandra Thrift API:

Another expression for a table in Cassandra is Column Family. The column family follows the Thrift API. As indicated by Thrift API in Cassandra, the segment family is a lot of lines that like this contain sections. These lines might be thin or wide. In different terms, the lines can control to be little or huge. To characterize Column Family, a client requires a line key and segment key. The line key is fundamentally an identifier of a line, and the segment key distinguishes a cell or segment in succession.

Cassandra's Keyspace Attributes:

There are three fundamental attributes in Cassandra's keyspace

• Replica Placement Strategy: this strategy will simply add replicas into the ring, we have few policies they are old network topology strategy, simple strategy, and network topology strategy.
• Replication factor: It is the number of devices within the cluster that will obtain models of the comparable data. 
• Column families: Keyspace is a compartment for a rundown of at least one segment of families. A section family, like this, is a compartment of an assortment of columns. Each line contains requested segments. Section families speak to the structure of your information. Each keyspace has in any event one and frequently numerous section families.

CRUD operation within Cassandra:

CRUD stands for creating, update, read, and delete. CRUD operations are utilized to handle data present in Cassandra. Separated from this, CRUD operations within Cassandra, a client can also check the request or the data.

Disadvantages of Cassandra:

• Cassandra doesn't give ACID or relational data features. If you ought to robust demand to ACID properties, Cassandra will not occur to fit within this chamber.
• Cassandra will not support join or subquery. You may be capable of obtaining a workaround during that one, though that might influence the execution and strengthen overhead.
• Cassandra will not aid aggregates, if you want to make a number of them, consider a different database.
• Reads are more moderate. Cassandra can be optimized from the start for quick writes. Reads weren't as enough of a matter; however, that immediately developed as more further use cases were acknowledged.

Conclusion:

Now We all understood that Cassandra means a NoSQL database. So it contributes a clarification for every problem wherever the whole of your wants is to hold a pretty significant write method, and you all need to possess a quite warm reporting system on the peak of data that is stored.  

For in-depth knowledge on Cassandra, click on below:

• Cassandra NoSQL
• How To Install Cassandra Ubuntu 14.04
• Cassandra Architecture
• CQL Datatypes in Cassandra
• CQL Collections in Cassandra
• Cassandra Data Types