Learning of SQL Day 5

 

Day 5: Creating and Dropping Tables

Introduction:

• Tables are fundamental building blocks in SQL databases. Today, we'll focus on creating and dropping tables.

Key Concepts:

• Table Creation: Setting up a new table to store data.

• Table Deletion: Removing an existing table from the database.

SQL Commands:

1. Creating a Table:

   • The CREATE TABLE statement is used to create a new table with specified columns and data types.

sql

-- Create a table named Courses with columns for CourseID, CourseName, and Credits
CREATE TABLE Courses (
    CourseID INT PRIMARY KEY,
    CourseName VARCHAR(255) NOT NULL,
    Credits INT
);

2. Checking Existing Tables:

   • Use the SHOW TABLES statement to list all tables in the current database.

sql

-- Show all tables in the current database
SHOW TABLES;

3. Dropping a Table:

   • The DROP TABLE statement is used to delete a table from the database.

sql

-- Drop the table named Courses
DROP TABLE Courses;

Practice Exercise:

1. Create a table named Books with the following columns:

   • BookID (INT, Primary Key)

   • Title (VARCHAR)

   • Author (VARCHAR)

   • PublishedYear (INT)

2. Verify the table creation by listing all tables.

3. Drop the Books table.

4. Verify the table deletion by listing all tables again.

Important Tips:

• Use meaningful column names to make your tables self-explanatory.

• Always ensure you have backups before dropping tables to avoid data loss.

Mastering the creation and management of tables will significantly enhance your database skills.