What is RDBMS (Relational Database Management Systems)?

August 1, 2022

What is RDBMS? Well, technically it stands for Relational Database Management Systems. It is the name of the system used to store, administer, query, and retrieve data from a relational database (RDBMS). The RDBMS offers administrative features for controlling data storage, access, and performance as well as an interface between users, applications, and the database.

This relational model was introduced by E. F. Codd and even today RDBMS is the basis of all modern database systems such as MySQL, Microsoft SQL Server, Oracle, etc.

What is RDBMS Table?

The records or data stored in RDBMS are in the form of objects that are known as Tables. It is a collection of related records or data and it also consists of different columns & rows. A record is an individual entry that exists in the table whereas the column holds information about every record in the table. Storing the data or records in a table is the easiest form of storage in RDBMS.

RDBMS Table Structure

We will look at the structure of how the data is stored in RDBMS. Here we are looking at a small table on Products Order information named (Products).

Order ID	Category	Region	City	Country	Customer_ID	Customer_name
CA-2018-126907	Office Supplies	Central	Chicago	United States	SM-20950	Suzanne McNair
CA-2021-115546	Technology	East	New York City	United States	AH-10465	Amy Hunt
CA-2021-115546	Office Supplies	East	New York City	United States	AH-10465	Amy Hunt
CA-2019-163587	Office Supplies	East	Dover	United States	EP-13915	Emily Phan
CA-2019-163587	Office Supplies	East	Dover	United States	EP-13915	Emily Phan
US-2021-106131	Technology	West	Aurora	United States	TP-21565	Tracy Poddar
US-2021-106131	Office Supplies	West	Aurora	United States	TP-21565	Tracy Poddar
CA-2019-160213	Office Supplies	East	Long Beach	United States	AR-10825	Anthony Rawles
CA-2018-157924	Office Supplies	West	Pasadena	United States	HA-14920	Helen Andreada
CA-2018-157924	Furniture	West	Pasadena	United States	HA-14920	Helen Andreada

The columns in the “Products” table above are Category, Region, City, Country, Customer ID, and Customer Name.

The database defines relationships in the form of tables. The tables are related to each other on data common in them. The relationship between the “Products$” table and the “People$” table is the Region column:

Region	Regional Manager
West	Sadie Pawthorne
East	Chuck Magee
Central	Roxanne Rodriguez
South	Fred Suzuki

Similarly, the relationship between the “Products” table and the “Returns$” table is the Order ID column-

Order ID	Returned
CA-2018-126907	Yes
CA-2021-115546	Yes
CA-2021-115546	Yes
CA-2019-163587	Yes
CA-2019-163587	Yes
US-2021-106131	Yes
US-2021-106131	Yes
CA-2019-160213	Yes
CA-2018-157924	Yes
CA-2018-157924	Yes

What is a FIELD in RDBMS?

A field is a column name that defines each record specifically. As in the above table, we have OrderDate, Region, Rep, Item, Units, Unit Cost, and Total are all Fields.

What is a Column in RDBMS?

A column is a vertical entity in a table that contains all information associated with a field in a table.

For example, a column in the Products table is Region, which represents region description as shown below –

Category

Office Supplies

Technology

Furniture

NULL Values –

NULL values are those values in a field that appears to be blank, which means the field is NULL with no value. It’s very important to understand that the NULL values are not equivalent to zero or spaces. It is the field that is intentionally kept blank at the time of data creation.