Common Database Operations: CRUD and Beyond

Common Database Operations
Database operations can be broadly categorized into two main groups: Data
Definition Operations and Data Manipulation Operations. Let’s break them
down:



1. Data Definition Operations
These operations define and modify the structure of the database. They include:

a. CREATE

 The CREATE operation is used to define a new database object, such as a
table, view, index, or database itself.
 SQL Example:

CREATE TABLE Employees (
ID INT PRIMARY KEY,
Name VARCHAR(100),
Age INT,
Department VARCHAR(50)
);

b. ALTER

 The ALTER command modifies an existing database object, such as adding,
deleting, or modifying columns in a table.
 SQL Example:

ALTER TABLE Employees ADD COLUMN Salary DECIMAL(10, 2);

c. DROP

 The DROP operation removes a database object, such as a table, index, or
view, and permanently deletes its data.
 SQL Example:

, DROP TABLE Employees;

d. TRUNCATE

 The TRUNCATE operation removes all rows from a table but does not
remove the table structure itself. It is faster than DELETE as it does not log
individual row deletions.
 SQL Example:

TRUNCATE TABLE Employees;


2. Data Manipulation Operations
These operations deal with the actual data inside the database and include:

a. SELECT

 The SELECT statement is used to retrieve data from one or more tables.
 SQL Example:

SELECT Name, Age FROM Employees WHERE Department = 'HR';

b. INSERT

 The INSERT operation adds new records (rows) into a table.
 SQL Example:

INSERT INTO Employees (ID, Name, Age, Department)
VALUES (1, 'Alice', 30, 'HR');

c. UPDATE

 The UPDATE operation modifies existing records in a table.
 SQL Example:

UPDATE Employees
SET Age = 31
WHERE ID = 1;