DEV Community

Vigneswaran Manivannan
Vigneswaran Manivannan

Posted on

Its been my first day class for SQL- 09-06-2025

At the 1st session, Today I got introduction about some basic terms such as Database, Types of Database..

Database

  • A database is an organized collection of structured data, which is stored electronically . It's managed by a database management system (DBMS).

Structured

  • It will be an organized level. That is an organized format contains tables. formed by rows and columns.

Unstructured-

No predefined format, It will be harder to analyze as it is an unstructured.
ex, Photos , videos

**

semi structured

It wont follow the table format.

DBMS-
A software which is used to interact with the database. In that we can store, manage( add, edit, remove), retrieve data.

Some key reason to use DBMS were,

  1. To organize and align a data, so that we can quickly retrieve the data.

2.For data integration, get accurate data with consistency.

  1. For security purpose. We can restrict to users accordingly.

4.Can be used by multiple users at same time.

  1. Can do backup and recovery option available.

*TYPES OF DBMS
*

1. Hierarchical DBMS.

  • Tree like hierarchy
  • One to many relationship
  • Data were stored as records, connected via parent- child link. -They store data in a tree-like structure so that it is easy to find and use ex, Org >> State >> region >> city.

2. Network DBMS.

  • Many to many relationship
  • Graphical structure ex, Book, Author name, publisher, borrower.

3. Relational DBMS.

-Stored in tables as rows and column.

-They do not support many to many relationships and have pre-defined data types that they can support. They are the most popular DBMS type in the industry.

ex, Oracle, MySQL, MS SQL

4. OO DBMS

-Object oriented DBMS.
-They store data in the form of objects. It supports the storage of miscellaneous data types.

ex, DB40, Object DB, Gemstone

5. No SQL DBMS.

-Unstructured, semi structured.

ex, document based, key value, graph data. Applicable for big data, social network.

*FEATURES OF DBMS
*

ACID

A- ATOMICITY- All steps to be succeed or none of the steps
C-CONSISTENCY-Data remains valid before and after any transaction.
I- ISOLATION- Can run independently.
D- DURABILITY - Data can be saved permanently, even after the crash.


Top comments (1)

Collapse
 
payilagam_135383b867ea296 profile image
Payilagam

Good start! Keep up the good writing!