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MySQL RDBMS

Learn, What is RDBMS, and common terms such as database tables, attribute, entity, Relational database table, etc.
Submitted by Apurva Mathur, on September 03, 2022

What is RDBMS (Relational Database Management System)?

MySQL is an open-source Relational Database Management System also known as (RDBMS). As the name suggests it is based on the relation between different rows and columns. A relational Database is a straightforward way of representing data in a table. In this database we have different rows and columns which are unique in the table and every row will be having one specific ID which would be again unique, this unique ID is commonly called a key. The relationship between the different columns is differentiated by the attributes of the tables.

There are some common terms that we will see in this tutorial let us learn them one by one.

Database Table

As we know, the table is simply used to keep records. Here also we use table rows and columns to keep the record of the entries. Every column in the table is an attribute and every row in the table is the data of that attribute.

Attribute

Attributes are simply the properties of any particular object. For example, we are asked to make the table that will record the student data, so here we have a table name = student_details so its attributes would be like Student_ID, Student_Name, Student_Rollno, Student_Phonenumber, Student_emailid, Student_Parentsno, etc. Attributes can be anything according to the situation. We have several types of attributes that we will see in upcoming tutorials.

Entity

The entity is something that is a real-world model. For example, We have a database COMPANY, and the entity type is EMPLOYEE. Here employees are the natural world person that has some existence.

Relational Database Table

To define the relationship between different tables we use a relational database table. Let us take the example.

Suppose we have three tables named "country", "states", and "city". These tables have the following attributes:

Country: Country_ID, Country_name.
State: State_ID, Country_ID, State_name
City: City_ID, State_ID, City_name

From these attributes you'll observe that the state table is related to the country table through the attribute Country_ID, In the same way, the city is connected to the state table through the state_ID.

Here in this table, we have Country_ID and Country_Name.

This is a "state" table, as we can see in this table; all the cities are linked with Country_ID.

So for example if I want to know the country name of State_ID 107 then I can just simply see the Country_ID it is associated with. Here, Country_ID would be 1003 and we'll see Country_Name in "Country" table where Country _ID is 1003 we'll get our country, i.e. "China".

In the same way, "city" table is related to "state" table, like if I want to know the state name of the city "patna" then I can simply see the State_ID it is associated with, here State_ID would be 102, and we'll check the State_Name in the "state" table where State_ID is 102, we'll get out answer, i.e. "bihar".

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