Hash table is a data structure that stores data in key-value pairs. It is also named as a dictionary or associative array. It stores data in a way that enables lookup and insertion in constant O(1) time. These properties of a hash make it one of the most useful data structures in a programmer's toolbox.
Implementation of the hash quite the same in Ruby, Java, Python. We just need to understand Pros and Cons of using it.
Learn how it works.
Data structure is a way of defining, storing & retriving of data in a structural & systemetic way.
A data structure may contain different type of data items
Q2: What are various data-structures available?
Data structure availability may vary by programming languages.
Commonly available data structures are list, arrays, stack, queues, graph, tree etc.
We have given an array and the task is to convert the array elements into string.
In this article, we are using two methods to convert - array to string conversion php.
To convert an Array to String with PHP, we can use two different built-in functions available in PHP.
These two functions only take one array at a time to convert it into a string.In PHP, the implode () method joins array elements and outputs them as a single string.
This is useful when you need to create one string out of a set of array values.
We are going to explain a very common question array to string conversion in PHP.
When it came to designing new applications, SQL databases were formerly the de-facto choice.
First, we'll need to rapidly review the technological concepts that underpin the two types of databases so that we can determine what distinguishes them and use that information to guide our future judgments.
The following are some of the most common SQL databases:MySQLPostgreSQLMicrosoft SQL ServerOracleMariaDBSQL databases are relational databases that adhere to E. F. Codd's relational model published in 1970.
To work with data, SQL databases use the Structured Query Language (SQL).
The following are some examples of common NoSQL databases:MongoDBCouchDBRedisElasticsearchCassandraThe requirement for scalability and flexibility, particularly among tech giants dealing with enormous and diverse sets of data, prompted the rise of NoSQL systems.
NoSQL databases are schemaless, which means that the tables and relationships between them are not rigorously defined.
One question always comes to our mind that, “What is the difference between Blockchain and Database ?” or “Is Blockchain a database?” Well, yes Blockchain is a decentralized ledger (database) containing records of transactions.
While storing data in the blockchain you should always remember that there is no ‘D’ in ‘CRUD’ operations.
Data stored in the blockchain is not controlled by any central entity, because of which we can get higher security and reliability.
Data stored is not limited up to the transaction details only, we can see that a huge data will be stored on its nodes in future including texts, images, videos, infographics and so on.
There are certainly other alternatives which we can opt to store data for our systems which we will discuss one by one.
It relies on a Distributed Hash Table and the BitTorrent protocol.