NoSQL Developers Hiring Guide

You Want Big Data, You Need NoSQL

Companies depend on data. And the bigger the company the more important data actually is. In fact, data has become a major driving force for nearly every aspect of doing business. From customer relations management, marketing, development, quality assurance, trend prediction, customer feedback, competitor assessment, refining operations, and even creating new streams of revenue, data touches everything.

You might think that any type of database will work for your business given the relationship between data and technology. Although that might be true for small businesses (where even a spreadsheet could work out fine), the more you grow, the faster you’ll find only one type of database is a good fit for your needs.

That database in question is of the NoSQL type. NoSQL stands for either Not SQL or Not Only SQL. Either way, NoSQL is a different breed of database than the standard relational type. Relational databases are also quite important to business, as they tend to drive platforms like WordPress, Drupal, Joomla!, and Xoops. But NoSQL tends to serve a much different purpose—big data.

So how is it possible that one database is perfectly geared toward applications that many large companies depend on, but another specifically targets big data?

Let’s unpack this.

Hiring Guide
Interview Questions
Job Description

Relational vs NoSQL Databases

The first thing we must do is clarify the difference between a relational database and a NoSQL database. The biggest difference between NoSQL and Relational databases is that NoSQL works with dynamic schema, which allows you to use unstructured data.

This means that you can build an application without having to construct the database schema first. Consider this: When you build an application with a relational database in mind, you must know that the application will require specific tables with certain rows and columns. Before you add that first bit of data to the database, you must define the schema. If you don't, you won't be able to successfully add data, which means you won't be able to connect your app to the database.

A NoSQL database, on the other hand, doesn't require structured data. In fact, data requirements can even change within your application without causing problems with the database. Because NoSQL databases work with unstructured data, it means they can handle different types of data, such as:

Video clips
Mobile device activity
Social media usage
Textual documents
Images

So you're not just limited to text-only entries.

Another difference is that relational databases are vertically scalable, but can have significant associated costs. Scaling a NoSQL database is significantly cheaper and more reliable.

NoSQL databases are better suited for modern applications with complex, constantly changing data sets, especially at scale.

Finally, another big advantage NoSQL databases have over relational databases is that they can store and process data in real-time. So not only are they more scalable, but they're also considerably more performant.

How Data is Stored

Let's take a look at a simple example. Let’s say you want to store information in both types of databases for the following:

ID
First_Name
Last_Name
Cell_Number
City

In a relational database, you create a table with the rows, as in:

First_Name

Last_name

Cell_Number

City

So you have a row. Now, when you want to add data, you add another row and your table now looks like this:

ID	First_Name	Last_name	Cell_Number	City
001	Robin	Goodfellow	5551234567	Boston

And that's how you build a table with a relational database. In a NoSQL database (such as MongoDB), you would create a document that would look like this:

{
"_id": 001,
"first_name": "Robin",
"last_name": "Goodfellow",
"cell": "5551234567",
"city": "Boston"
}

Now that you have a fundamental understanding of what a NoSQL database is, what do you need to know to hire those who will develop with those databases? One of the most important things you must understand is that most relational databases use the SQL query language for running queries against a database. With NoSQL databases, there is no "universal" query language. Because of that, your business will have to decide which NoSQL database it will depend on.

But it's not just a simple matter of selecting which NoSQL database you'll use, as there are different types of NoSQL databases.

Document Oriented

A document-oriented NoSQL database is designed to store, manage, and retrieve data stored in documents. This is also called a semi-structured database.

Key-Value Stores

This is the simplest type of NoSQL database. In this type of NoSQL database, every data object is a key-value pair that consists of a name and a value. This is the closest thing you'll find to a relational database structure in a NoSQL database (only the database has just 2 columns).

Column-Oriented Databases

A column-oriented database stores everything in, as you guessed, columns. Columns tend to be of the same type and benefit from a very efficient form of compression, which makes these types of NoSQL databases incredibly fast.

Graph Databases

This type of NoSQL database focuses on the relationship between data elements and is optimized to capture and search connections between data elements, which overcomes the significant overhead associated with multi-table JOINs in relational databases. This type of NoSQL database tends to be used alongside relational databases.

Because you have so many choices of NoSQL databases, and since there is no universal query language, you must not only first select the NoSQL database you're going to use, you need to hire developers who are familiar with that particular database query language. For example, you wouldn't hire a developer familiar with CouchBase for MongoDB. The CouchBase query language is N1QL, whereas the MongoDB query language is MQL.

This is a crucial point to consider when hiring any developer who will be developing a project that will interact with a NoSQL database.

Conclusion

NoSQL databases are absolutely crucial for big businesses that need to work with big data. And hiring developers to work on those databases must start with the decision on which NoSQL database to use. Once you've decided on a database, you can then begin the process of hiring a developer familiar with the specific query language so they can successfully integrate their applications into your data.

What are some of the most popular NoSQL databases?

MongoDB, CouchBase, Apache Cassandra, Redis, and Apache HBase.

What are the 4 types of NoSQL databases?

Document-oriented, key-value stores, column-oriented, and graph.

What is the difference between horizontal and vertical scaling?

Horizontal scaling is to scale by adding more machines into a pool of resources.
Vertical scaling is to scale by adding more power (CPU, RAM) to an existing machine.

Name some key advantages NoSQL databases have over relational databases.

NoSQL supports semi-structured data.
NoSQL doesn’t depend on schema.
NoSQL has a much higher read/write throughput.
NoSQL easily scales horizontally.
NoSQL supports terabytes and petabytes of data.
NoSQL provides support for business analytic tools.
NoSQL can be hosted on cheaper hardware.
NoSQL supports In-memory caching for increased query performance.
NoSQL offers a much faster development life cycle.

We are looking for a talented software engineer with a high-level mastery of NoSQL databases. You must have a solid grasp of the particular NoSQL database technology we use for app development and data interaction. You will also be responsible for integrating front-end elements built by your co-workers into the database. Therefore, a basic understanding of front-end technologies is necessary as well.

Responsibilities

Design, build and maintain efficient and reusable databases and have the skills to effectively query and integrate them into applications.
Integrate data storage solutions.
Implement performance and quality modes.
Identify bottlenecks and bugs and resolve issues.
Monitor the performance of the deployed databases to find ways to improve them.
Collaborate with cross-functional teams to define and design new features.
Stay up to date with new technology trends, applications, and protocols.
Help maintain code quality, organization, and automatization
Analyze user requirements to help inform application design.
Define application objectives and functionality.
Align application design with business goals and customer needs.
Produce detailed documentation.
Recommend changes to existing databases and the infrastructure used to build them.
Ensure continuous professional self-development.
Integrate user-facing elements developed by front-end developers with server-side logic.
Write reusable, testable, and efficient code.
Design and implement low-latency, high-availability, and performant databases.
Implement security and data protection.
Integrate data storage solutions.

Skills and Qualifications

Degree in Computer Science or related field.
Experience with one or more NoSQL databases.
Basic understanding of front-end technologies, such as HTML5 and CSS3.
Understanding of the principles behind scalable applications.
Fundamental understanding of version control systems (such as Git).
Solid problem-solving skills.
Excellent written and verbal communication.
Good organizational skills.
Ability to work as part of a team.
Attention to detail.
Understanding the nature of asynchronous programming and its quirks and workarounds
A positive attitude.

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