For anything but the simplest web site, you will have to store data somewhere. Fortunately, data storage is a problem that has been worked on since the earliest computers were designed, and there have been many decades of research into the best ways of storing and retrieving data of all types, at scales ranging from small product catalogues to industrial systems tracking and storing millions of variables and events per second.
It will be important to note that there is no such thing as the best Database in as much as there is no best programming language. Saying a database is better than another is like saying apples are better than oranges.
See them as tools and you should only choose one based on your preference and the complexity of the job at hand. However, saying a Database or programming language is the best could become an endless debate and won’t be of value to you.
Our choice for the top ten databases to learn is based on their popularity and how often they are required in the job market. Also, our list of databases is not in any order.
Best Relational Databases To Learn
For a long time, relational databases such as MySQL dominated the database scene, but an increasing number of applications now use “NoSQL” databases, such as MongoDB or Redis.
A relational database refers to a database that stores data in a structured format, using rows and columns. This makes it easy to locate and access specific values within the database.
Relational databases are referred to as such because you can express relationships between the data in the schema. Relational databases are structured into tables, where an individual record in that database is called a row, and each field within that record is called a column, and all rows have the same columns with the same types.
Below is a list of our top relational databases you will most often come across in the wild.
MySQL is among the most widely used relational databases. It was initially released in 1995 and developed by oracle.
It is implemented in C and C++.
It is arguably the most popular database and is generally among the first databases to be adopted by beginners. Given the number of programming languages it supports, I’m almost certain your favorite programming language will find itself on the list.
PostgreSQL is a popular open-source relational database with object-oriented extensions such as user-defined types/functions and inheritance.
Do not underestimate this database based on the fact that it is open source. This piece of software has all it takes to compete with the most sophisticated proprietary database you can imagine.
It is implemented in the C programming language.
PostgreSQL database happens to be very recommended these days and is never far from the top 2 positions in whatever ranking you decide to base your judgment on. I recommend it too.
3. Oracle Database
Unlike MySQL and PostgreSQL, Oracle is a commercial relational database with a restricted free version.
The Oracle database is mostly used in large corporations and is a monster in terms of security and efficiency and I guess that’s why it is not free.
Let it not frustrate you, the free databases are pretty good too especially PostgresSQL and are capable of running almost any app you may want to create.
4. Microsoft SQL Server
Like Oracle, Microsoft SQL server is a commercial relational database with a restricted free version.
The Microsoft SQL Server database is highly recommended for those working on the Microsoft platform.
SQLite is a free open-source database developed by Dwayne Richard Hipp in the year 2000 and implemented with the C programming language.
This database is definitely the best to learn SQL with because it is lightweight and can be installed even on very old PCs.
MariaDB is a MySQL application compatible open-source Relational Database Management System, enhanced with high availability, security, interoperability, and performance capabilities. With MariaDB ColumnStore a column-oriented storage engine is also available.
MariaDB is available on almost all platforms and opensource, though there exists a commercial enterprise subscription.
MariaDB is like a little sister to MySQL and hence, any valid MySQL query is also valid in MariaDB but the reverse is not true.
Best NoSQL Databases To Learn
NoSQL databases are non-tabular and store data differently than relational tables. NoSQL databases come in a variety of types based on their data model. The main NoSQL database types are document, key-value, wide-column, and graph.
Below is a list of the top non relational databases to learn.
MongoDB is one of the most popular document stores available both as a fully managed cloud service and for deployment on self-managed infrastructure.
MongoDB is opensource, available on all major operating systems, and implemented in C++. It is definitely the non-relational database to learn due to its popularity.
Cassandra is a Wide-column store, based on ideas of Big-table and DynamoDB.
Though it is a relatively young database (released in 2008), Cassandra has seen its popularity increase during the years and is now among the top databases to learn for those intending to work with a no-relational database.
Redis is an in-memory data structure store, used as database, cache and message broker.
It is opensource, available on the major operating systems and was developed in 2009 by Salvatore Sanfilippo.
In my opinion, Redis is definitely not a database to learn for a beginner or anyone intending to have a job. This is because job offers that require it as a skill are pretty scarce. Nevertheless, it is among the most popular open-source databases that exist.
Elasticsearch is a distributed, RESTful modern search and analytics engine based on Apache Lucene. It is open-source and available on major operating systems.
SQL or NoSQL?
Many NoSQL databases are promoted based on the performance advantages they offer over relational databases, and the benefit of avoiding doing any schema design or migrations (changes to the schema that require the stored data to be updated to match the new schema), but they do have their downsides too.
Much of the power from relational databases comes from the fact that tables can be “joined” based on these relationships to get a result in a single query from multiple different tables.
Most NoSQL databases do not allow this kind of joining, so can work out to be less performant for certain types of query. This is often worked around by repeating information inside documents (for example, author name, rather than linking to an author table), a process known as denormalization.
A database that is normalized does not contain any repeated or redundant information. Although denormalized tables are not necessarily problematic, they do make it easier to introduce inconsistencies, and can make it harder to update data that appears in many places in the database.
Some relational databases are now adopting techniques from the NoSQL world. For example, PostgreSQL supports a JSON column type, rather than having to store all the data in a flat table.
Whether or not to go relational or NoSQL depends on the type of data you have. Although NoSQL databases avoid the constraint of formally specifying a schema, you will often want to have some type of schema to keep a reasonable data structure, either to be read from in your application or to create indexes.
NoSQL databases can also be faster to write to, so if you have many more writes than reads, this can be a better fit, but for most other types of data, a relational database will serve you well.
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