June 11, 2021-6 minutes to read

Erin Schaffer

Relational databases are a useful way to work with structured data. They represent data in an organized, clear way that makes it easy to see and understand the relationships between data structures. Today, we’ll delve into relational databases, discussing their benefits, uses, and more.

We will introduce.

  • What is a relational database?
  • Advantages of relational databases
  • Use of relational databases
  • What is SQL?
  • Properties of relational tables
  • Relational database instance
  • Summary and next steps

What is a relational database?

Relational databases, or SQL databases, store data in tables and allow easy access to related data points. In a relational database, each row in a database table is a record with a unique identifier, called _ key _, and each column holds an attribute of the data.

The tables in a relational database are ** based on the _ relational model _**, which is a simple, intuitive way to represent data. Let’s look at some of the basic concepts of a relational data model in relation to a sample table. The relationship is “student” and the properties are _” name _”, “student ID”, and “age”.

students

  • Properties. Columns in a table. Attribute defines a relationship, such as _First_Name_ or _Student_ID_.
  • Relational patterns. Represents the name of the relationship and its attributes. For example, _Student (First_Name, Student_ID, Student_Age) _ is the relational mode of _Student_.
  • Tuples. A single row of a table containing one record. The table above has three primitives, one of which is _Elliot 17 20_.
  • Degrees. The number of attributes in a relationship. There are three relationships above.
  • Loyalty. The number of primitives in a relationship. There are three relationships above.

Relational database management system

A relational database management system (RDBMS) is software that records, manipulates, and retrieves data in a relational database. This software is a great way to handle relevant data points that need to be maintained in a secure and consistent manner.

MySQL is the most popular open source relational database management system (RDBMS). Some other popular relational database software include.

  • MongoDB
  • PostgreSQL
  • Microsoft SQL Server
  • Oracle database
  • Amazon Relational Database Services (RDS)
  • IBM Informix

Non-relational databases

A non-relational database, or NoSQL database, stores data in a non-table manner. They use a variety of different data models to access and manage data types. NoSQL databases are ideal for applications with large data sets because they are highly responsive, extensible, and adaptable.

NoSQL databases provide highly functional apis and data types that are built for their corresponding data models and optimized for higher performance.

There are four main types of NoSQL databases.

  • The key value store
  • Graphic database
  • Column-oriented databases
  • Document storage

Note: NoSQL stands for _ not just SQL_, because you can use them with or without SQL.

Advantages of relational databases

Using a relational database model for data management and data storage has many advantages, including.

  • Flexibility. It is easy to extend, update, and delete data as needed.
  • Atomicity. Atomic transactions ensure that you either commit the entire transaction or have no transaction at all. If the connection is lost, the relational database reverts to its previous state.
  • Persistence. Changes made to the database are permanent, even in the event of a system crash.
  • Continuity. The only data that is allowed to be written to the database is data that follows data validation rules.

Use of relational databases

Relational databases are useful for many different things, such as.

  • Application development
  • The data warehouse
  • Data maintenance in applications
  • Storing structured data
  • Logging application
  • And so on.

They are also useful in many different industries, for example.

  • Retail and e-commerce

  • The financial sector

  • The banking sector

  • The insurance industry

  • Information technology (it)

  • The telecoms industry

  • Medical and health care

  • manufacturing

  • And so on.

What is SQL?

SQL, or structured Query Language, is a programming language for processing data in relational databases. All major relational database management systems use SQL as their database language.

SQL is the standard choice because of its benefits. With SQL, the user can.

  • Access the data in their RDMS
  • Describe, define, and manipulate data
  • Use SQL modules, libraries, and precompilers to embed them in other programming languages
  • Create and drop databases and tables
  • Sets the permissions for tables, processes, and views

You can use SQL statements to interact with your relational database. These commands are organized into three different groups.

  • Data Definition Language (DDL)

    • create
    • To change the
    • undo

  • Data Manipulation Language (DML)

    • Choose (SELECT)
    • INSERT
    • update
    • DELETE

  • Data Control Language (DCL)

    • awarded
    • undo

Let’s look at how to use one of these commands. Here’s how to use the CREATE DATABASE command.

CREATE DATABASE DatabaseName;
Copy the code

If you want to create two databases and then display your database list, you can do so.

CREATE DATABASE sampleDB1;
CREATE DATABASE sampleDB2;
SHOW DATABASES;
Copy the code

Note: The SHOW DATABASE command is used to display your DATABASE.

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Properties of relational tables

Let’s explore some of the properties of relational tables.

Each row is unique

No two rows in a table are the same.

The value is atomic

Atomic values cannot be broken down into small pieces. Relational tables do not contain duplicate group or multi-valued attributes. This simplifies data manipulation.

Column values are of the same type

Based on the data type, all values in a column come from the same domain. This allows simplified data access because you can determine what data types are contained in a given column.

The order of the columns is not important

Columns can be retrieved in any order. This allows users to share the same table without worrying about its organization.

The order of the rows doesn’t matter

Rows of a relational table can be retrieved in any order. Adding new data to the table does not affect existing queries.

Each column has a different name

Since the order of the columns is not important, they must be referred to by name. The name of a column need not be unique throughout the database, but only in the relationship to which it belongs.

Relational database instance

Relational databases work in many different situations. Let’s say a university wants to maintain information about its students, departments, and tutors. We can do this easily with a relational database. The following table shows the structure of a relational database and some sample data records.

Students table

The database has three tables that store the same type of data records in an organized way. Once all the data has been defined and built into the database, you can start using a database management system (DBMS) to retrieve information from different tables.

By Erin Schaffer

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