README.md

🏗️ Project 3: Model Schema Builder

🌟 Overview

Get ready for Schema Optimizer, where you’ll design and secure an ML database schema using DDL, DCL, and Triggers! This project builds a robust structure for model data, perfect for your ML-Interview-Preparation-Hub portfolio to show scalable design. 🚀

📊 Project Details

• Scenario: You’re a database architect for an ML platform. Your task is to create tables for models and predictions, secure access, and automate logging.
• Goals: Build tables, set permissions, add triggers, and document schema.
• SQL Skills: DDL (CREATE, ALTER), DCL (GRANT), Triggers.

📋 Tasks

1. Create models (model_id INT, trained_date DATE) and predictions tables.
2. Add constraints (e.g., primary keys, foreign keys).
3. Grant read-only access to analysts using DCL.
4. Create a trigger to log prediction inserts.
5. Create a log table for trigger data.
6. Test the schema with sample inserts.
7. Document for portfolio use.

💻 Sample Solution

-- Task 1 & 2: Create Tables with Constraints
CREATE TABLE models (
    model_id INT PRIMARY KEY,
    trained_date DATE NOT NULL
);
CREATE TABLE predictions (
    prediction_id INT PRIMARY KEY,
    model_id INT,
    score FLOAT,
    prediction_date DATE,
    model_name VARCHAR(50),
    FOREIGN KEY (model_id) REFERENCES models(model_id)
);

-- Task 3: Grant Permissions
CREATE ROLE analyst;
GRANT SELECT ON models, predictions TO analyst;

-- Task 4 & 5: Create Log Table and Trigger
CREATE TABLE prediction_log (
    log_id SERIAL PRIMARY KEY,
    prediction_id INT,
    insert_time TIMESTAMP
);
CREATE OR REPLACE FUNCTION log_prediction()
RETURNS TRIGGER AS $$
BEGIN
    INSERT INTO prediction_log (prediction_id, insert_time)
    VALUES (NEW.prediction_id, CURRENT_TIMESTAMP);
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER prediction_insert
AFTER INSERT ON predictions
FOR EACH ROW EXECUTE FUNCTION log_prediction();

-- Task 6: Test Schema
INSERT INTO models VALUES (101, '2025-04-01');
INSERT INTO predictions VALUES (1, 101, 0.85, '2025-04-15', 'BERT_v1');
SELECT * FROM prediction_log;

-- Task 7: Document (See Portfolio Tips)

Explanation:

• DDL defines tables with constraints.
• DCL secures access for analysts.
• Triggers automate logging of inserts.
• Tests verify schema integrity.

🎯 Expected Outcome

• A secure, functional ML schema.
• A log table tracking prediction inserts.
• A portfolio-ready schema design doc.

💼 Portfolio Tips

• Add schema SQL to irohanportfolio.netlify.app.
• Write a README explaining design and ML use (e.g., model tracking).
• Diagram the schema with tools like Lucidchart.
• Tag skills: DDL, DCL, Triggers.

🔥 Challenge

Add a TCL transaction to ensure atomic inserts across tables.

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