Create, Read, Update, and Delete operations (CRUD operations)

📌 What are CRUD Operations?

CRUD stands for Create, Read, Update, and Delete — the four basic operations for interacting with data in a database system. These are fundamental actions for managing persistent data and are crucial for any Business Analyst (BA) to understand when working with databases or IT systems.

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🔑 Overview of CRUD Operations

Operation	Action	SQL Command Used
Create	Add new data/record to a database	INSERT
Read	Retrieve or view data from a database	SELECT
Update	Modify or edit existing data	UPDATE
Delete	Remove existing data/record	DELETE

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✅ Detailed Explanation of Each Operation

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1. CREATE - Adding New Records

• Purpose: To insert new rows of data into a table.

Syntax:

sqlCopyEditINSERT INTO table_name (column1, column2, ...) 
VALUES (value1, value2, ...);

Example:

sqlCopyEditINSERT INTO employees (name, age, position, salary) 
VALUES ('Alice Johnson', 30, 'Data Analyst', 50000);

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2. READ - Retrieving Data

• Purpose: To fetch data from a table for viewing or processing.

Syntax:

sqlCopyEditSELECT column1, column2, ... FROM table_name WHERE condition;

Example:

sqlCopyEditSELECT name, position FROM employees WHERE age > 25;

• To get all data:

sqlCopyEditSELECT * FROM employees;

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3. UPDATE - Modifying Existing Records

• Purpose: To update existing data in a table.

Syntax:

sqlCopyEditUPDATE table_name 
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example:

sqlCopyEditUPDATE employees 
SET salary = 55000 
WHERE name = 'Alice Johnson';

⚠️ Important: Always use a WHERE clause to avoid updating all records unintentionally.

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4. DELETE - Removing Records

• Purpose: To delete data from a table.

Syntax:

sqlCopyEditDELETE FROM table_name WHERE condition;

Example:

sqlCopyEditDELETE FROM employees WHERE name = 'Alice Johnson';

⚠️ Caution: Omitting WHERE clause will delete all rows in the table.

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🧭 CRUD Operations Example on a Table

Sample Table: employees

id	name	age	position	salary
1	John Doe	28	Developer	60000
2	Jane Smith	32	Manager	75000
3	Alice Johnson	30	Data Analyst	50000

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Operation	SQL Command Example
Create	INSERT INTO employees (name, age, position, salary) VALUES ('Bob Martin', 29, 'Tester', 45000);
Read	SELECT * FROM employees WHERE position = 'Manager';
Update	UPDATE employees SET salary = 80000 WHERE name = 'Jane Smith';
Delete	DELETE FROM employees WHERE id = 3;

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🎯 Importance of CRUD for Business Analysts

Reason	Explanation
Understand Data Flow	BAs need to know how data is created, accessed, updated, and deleted.
Requirement Specification	Accurately define system requirements related to data management.
Data Validation and Analysis	Ensure that the data aligns with business needs and integrity.
Communicate with Developers	Specify how data operations should be handled in the system.
User Story Creation in Agile	Describe data manipulation needs in user stories.

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🚀 Summary

CRUD Operation	Action	SQL Command
Create	Add new data	INSERT
Read	Retrieve and display data	SELECT
Update	Modify existing data	UPDATE
Delete	Remove data	DELETE