EXAMINING RELATIONAL DATABASES
- Applying aggregate SQL function count, SUM, MAX, MIN to the employees’ table (“SQL COUNT (), AVG () and SUM () Functions“, 2020).
- SELECT SUM(Salary) AS employees_salaries FROM tblEmployees;
- SELECT MAX(Salary) AS max_salary FROM tblEmployees;
- SELECT MIN(Salary) AS min_salary FROM tblEmployees;
- SELECT AVG(Salary) AS avg_salary FROM tblEmployees;
- Finding the number of employees in technology department (“SQL COUNT (), AVG () and SUM () Functions“, 2020).
SELECT COUNT (*) AS employes FROM tblEmployees WHERE Department=’Technology’;
- Basic categories of NoSQL database.
There are many NoSQL databases currently available where some of them open-source while other some premium products. Many of them were built to serve for very different purposes. The NoSQL is grouped into four basic categories: the following (“Types of NoSQL Databases,” 2020).
- Document NoSQL Databases
NoSQL documents are used to store data in the form of BSON, JSON, or XML format. The data stored can be queried the same way as the data objects used in software, thus reducing the translation required to utilize it. When going back and forth between applications and storage, SQL data must also be assembled and disassembled (“Types of NoSQL Databases” 2020). These databases are familiar to application developers as they can restructure their software structures as per their data structures since application requirements keep changing over time. This kind of flexibility speeds development because, in essence, data is viewed like a code managed by developers. The most commonly used databases of NoSQL documents are designed with a scale-out design that offers an exact route to both data volumes and traffic scalability.
- Key-Value Stores
The key-value store is the simplest type of NoSQL database that stores database elements as a key-value pair consisting of a label and element. Key-Value Store NoSQL database is like a relational database with only two columns: the feature and the value (“Types of NoSQL Databases,” 2020). Key-value store databases are essential for storing reasonably necessary information, like details about a customer. There are several different key-value store databases, but the most popular is Redis, which is very flexible since it can be used with other languages and tools. It can also be used for a wide variety of purposes. In addition to that, key-value store databases are open-source with enterprise options available for users with significant requirements.
- Column-Oriented NoSQL Databases
A Column-Oriented database is organized as a column array as opposed to most relational databases that store data in rows (“Types of NoSQL Databases” 2020). If you want to run analytics on a small number of columns, the data stored can be extracted directly from individual columns without consuming space with unnecessary data. Columns also have the same shape and benefit from more efficient compression, making for much faster reading. Column-Oriented databases are more potent for analytics though the way they write data makes them difficult to be highly reliable because processing all columns needs multiple write events on the disk.
- Graph NoSQL
Graph NoSQL insists on the relationships between elements of the data. Every single entity is stored as a node. The ties between the elements are called interactions or relationships. Connections, which are premium components of the graph NoSQL, are stored directly in a graph database. The link is inferred in relational databases when using data to describe the relationships. A graph database is optimized to resolve the overhead associated with JOINing multiple SQL tables to capture and search the relations between data elements (“Types of NoSQL Databases” 2020). Graph databases are multidimensional relative to the relational databases. They demonstrate not only essential tables-data relationships but also more complicated and multifaceted ones.
- Functions that NoSQL can perform that extend what SQL can do.
NoSQL databases are now becoming popular in the current database landscape. Their advantages they pose are making them a real game-changer in the enterprise arena (“Different types of NoSQL databases and when to use them | Packt Hub,” 2020). Significant data handling, elastic scalability, and open-source features make NoSQL an appealing option for many companies looking to integrate into Big Data. The following capabilities of NoSQL exceed what SQL can do.
- Elastic scaling
Database administrators who interacted with earlier RDBMS were focused on scaling up by purchasing multiple servers, which became costly as the database load has been growing. This made scaling the database on earlier relational databases more complicated as the data continued to grow (“Different types of NoSQL databases and when to use them | Packt Hub,” 2020). The current NoSQL databases are designed in ways that can allow its expansion horizontally and transparently by considering the benefit brought by new nodes. They are also designed with low-cost hardware in memory, which allows servers to be added or removed from the data layer without application downtime in NoSQL.
- Big Data handling
The increased demand to accommodate the rise in data volumes has been a challenge to RDBMS, which has a limitation of data volumes that can be handled by a single RDBMS, unlike NoSQL databases, which can accommodate any data volume. Hadoop is one of the enablers of some of the types distributed NoSQL databases since it has enabled the spreading of data across thousands of servers with little performance reduction (“Different types of NoSQL databases and when to use them | Packt Hub,” 2020). This outstrips different function which RDBMS can handle regardless of how big its size is.
References
SQL COUNT (), AVG () and SUM () Functions. W3schools.com. (2020). Retrieved 30 August 2020, from https://www.w3schools.com/sql/sql_count_avg_sum.asp.
Different types of NoSQL databases and when to use them | Packt Hub. Packt Hub. (2020). Retrieved 30 August 2020, from https://hub.packtpub.com/different-types-of-nosql-databases-and-when-to-use-them/.
Types of NoSQL Databases. MongoDB. (2020). Retrieved 30 August 2020, from https://www.mongodb.com/scale/types-of-nosql-databases.