Relational Database


What is a relational database management system

What is a Relational Database Management System?

A relational database management system (RDBMS or just RDB) is a common type of database whose data is stored in tables.

You’ll find that most databases used in businesses these days are relational databases, as opposed to a flat file or hierarchical database.

Relational databases have the clout to handle multitudes of data and complex queries, whereas a flat file takes up more space and memory, and is less efficient.

So modern databases use multiple tables as standard. The data is stored in lots and lots of tables, or ‘relations’. These tables are divided into rows (records) and columns (fields).

See the data visualization in action:

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Much like the relationships between data in an entity’s relationship diagram, the tables in the relational database can be linked in several ways:

  • Characteristics of one table record may be linked to a record in another table
  • A table record could be linked to many records in another table
  • Many table records may be related to many records in another table.

What’s an SQL Query?

An SQL query is how you access the data. SQL stands for Structured Query Language.

Using an SQL query, you can create and delete, or modify tables, as well as select, insert, and delete data from existing tables. (Learn more about SQL performance tuning).

Benefits of Relational Databases

If you want to design a data storage system that makes it easy to manage lots of information, and is scalable and flexible, the relational database is a good bet.

  • Manageability: for starters, an RDB is easy to manipulate. Each table of data can be updated without disrupting the others. You can also share certain sets of data with one group, but limit their access to others – such as confidential information about employees.
  • Flexibility: if you need to update your data, you only have to do it once – so no more having to change multiple files one at a time. And it’s pretty simple to extend your database. If your records are growing, a relational database is easily scalable to grow with your data.
  • Avoid Errors: there’s no room for mistakes in a relational database because it’s easy to check for mistakes against the data in other parts of the records. And since each piece of information is stored at a single point, you don’t have the problem of old versions of data clouding the picture.

Challenges of Relational Databases

  • Scalability: Because relational databases are built on a single server. This means, in order to scale, you’ll need to purchase more expensive hardware with more power, storage, and memory.
  • Performance: Rapid growth in volume, velocity, variety, and complexity of data creates even more complicated relationships. Relational databases tend to have a hard time keeping up, which can slow down performance.
  • Relationships: Relational databases don’t actually store relationships between elements, which makes understanding connections between your data reliant on other joins.

Relational Databases FAQ

What Makes a RDBMS Relational?

Relational refers to the mathematical way to describe tables of structured data. Relations offer a straightforward way to store and sort data with minimal redundancy and few complications. RDBMS manage tables, which are mathematically known as relations. Additionally, the relational term has been used to describe the way objects in a database interact.

What is the Difference Between DBMS and RDBMS?

The major difference between DBMS and RDBMS is the way each stores information. DBMS stores data in hierarchical or navigational form, meaning that it is structured as a node in a tree. RBDMS can store data in tables, as well as create unique tables that store the relations between them. This allows for sets to be accessed more easily.

What are Examples of RDBMS?

Some of the most popular RDBMS examples include Microsoft’ SQL Server, Oracle Database, MySQL, and PostgreSQL.

How Do You Create a Relational Database?

Relational databases are made of tables containing data. To create such a database, the first step is to create the tables necessary to hold the expected data. Once the tables are ready, the next step is to determine their relation to each other and create a hierarchy that defines how they interact.

How Does a Relational Database Work?

To store data, relational databases create separate tables for each set. These tables are then organized into columns which store a single type of data. To represent a single item in a relational database, the data gets presented in a row, which collects its data from every related table.

What is a Relational Database in SQL?

SQL is a type of RDBMS which was built to create, manage, and query relational databases more easily and effectively. Data in SQL is stored in separate databases that can be hierarchically related to others, which can be easily updated and can hold stored procedures.

Why is it Called a Relational Database?

There are two major reasons, though they are related. The first stems from relational algebra, which describes a method of expressing data in tables known as relations. Relational databases can be rearranged in diverse ways to visualize data without having to manipulate the tables themselves. Data is expressed as the relation between each table in unique rows.

Is MySQL a Relational Database?

MySQL is based on SQL, which is an RDBMS. As such, it does produce relational databases.