Types of Commands in SQL

 

The Toolbox of SQL Commands: Unveiling Unseen Magic!

Salutations, new SQL Sorcerers! Are you prepared to unlock the secrets of SQL commands? The magical words that animate databases? Now let's venture on an enchanting journey. We will unearth the magical toolbox of SQL commands.

Welcome to the realm of enchantment. This is SQL.

Meet the Magical Commands

In the SQL realm, we have five special spell types. Yes, these have a unique function. Let's learn about them one by one.

1. DDL: The Spell of Creation and Structure 🏰

DDL stands for (Data Definition Language). These spells are like blueprints for the creation and organization of our magical castle, more commonly known as the database. DDL assists in creating, modifying, and deleting structures. These actions take place within our castle.

CREATE Spell

This particular spell helps in the creation of new magical rooms. These rooms are essentially tables within our castle:

CREATE TABLE Wizards (Name TEXT, Power TEXT);

ALTER Transformation

The ALTER spell allows for modification of existing rooms. In our context, rooms are synonymous with tables. Or it can make them either bigger or smaller:

ALTER TABLE Wizards ADD COLUMN Age INT;

DROP Disappearing Act

The DROP spell offers the ability to make a room disappear. These rooms are tables within our magical castle:

DROP TABLE Wizards;

2. DML - The Spell of Potion Brewing 🧪

DML (Data Manipulation Language) spells function as recipes. They brew magical potions. These potions mimic data. They assist in adding, updating, retrieving, and vanishing data. All this happens within our castle.

INSERT Potion Recipe

This spell is able to brew new potions. This process involves adding data. Our magical cauldron is the vessel. It's a table:

INSERT INTO Potions (Name, Power) VALUES ('Invisibility Elixir', 'Become Invisible');

UPDATE Potion Upgrade

The UPDATE spell is used to modify an existing potion. This process involves updating data. We aim to make the potion more potent:

UPDATE Potions SET Power = 'Super Invisibility' WHERE Name = 'Invisibility Elixir';

DELETE Potion Vanish

The DELETE spell is employed for making a potion disappear. It involves deleting data from our magical cauldron. Our 'cauldron' metaphorically represents a table:

DELETE FROM Potions WHERE Name = 'Invisibility Elixir';

3. DCL - The Spell of Permissions and Control 🛡️

DCL (Data Control Language) spells are akin to magical shields. They control access to our "castle" (database). These spells help manage who can enter and what they can do.

GRANT Access Permission

This spell grants special access (permissions) to other wizards:

GRANT SELECT ON Potions TO ApprenticeWizard;

REVOKE Access Restriction

The REVOKE spell removes previously granted access permissions:

REVOKE SELECT ON Potions FROM ApprenticeWizard;

4. TCL - The Spell of Transaction Management 🔄

TCL (Transaction Control Language) spells resemble enchanted bookmarks. These help us manage our magical book. Here, the 'magical book' refers to our database. It ensures proper recording of changes.

COMMIT Magic Seal

This spell sets a magical seal. It saves all changes made:

COMMIT;

ROLLBACK Time Reversal

The ROLLBACK spell reverses any unwanted changes. It is like turning back time:

ROLLBACK;

5. DQL - The Spell of Wisdom and Insight 🧠

DQL (Data Query Language) spells function like magical lenses. These lenses let us delve into our magical book. They also allow us to pose queries. This helps us to acquire knowledge.

SELECT Wisdom Gaze

The SELECT spell lets us gaze into our magical book. We can retrieve specific information:

SELECT * FROM Wizards;

Ready to Weave Your SQL Magic?

You've unveiled the SQL command magic toolbox! With these magic spells, you can create, brew, control, manage, and finally, gain wisdom from your database castle.

Practice these spells, and soon you will become a true SQL sorcerer. May your spellcasting be joyful! 🌟