SQL Mini Engine

A lightweight SQL engine built in Python that parses and executes simple SQL queries (SELECT, COUNT, WHERE) against CSV and CCOL (custom columnar format) data.

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✨ Features

• SQL Parser (Step 2)
• Query Execution Engine (Step 3)
• Interactive CLI (Step 4)
• Unit Tests (Step 5)
• Benchmarks (Step 6)
• CCOL Writer/Reader (Step 7)
• Selective Reads (Step 8)
• String Offsets Optimization (Step 9)

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🔧 Installation

Clone the repository and install dependencies:

git clone https://github.com/Jnaneswari19/sql-mini-engine.git
cd sql-mini-engine
pip install -r requirements.txt

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🚀 Usage

Run queries via CLI:

python -m sqlmini.cli "SELECT name, age FROM people WHERE age >= 30;"

Run tests:

python -m pytest

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📝 Example Queries

python -m sqlmini.cli "SELECT COUNT(*) FROM sales;"
python -m sqlmini.cli "SELECT name FROM people WHERE age < 25;"
python -m sqlmini.cli "SELECT COUNT(age) FROM people WHERE age >= 30;"

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📊 Benchmarks

CSV vs CCOL

Query	CSV (s)	CCOL (s)
SELECT * FROM people;	0.000133	0.000735

Selective Reads

Format	Time (s)
CSV selective read	0.000147
CCOL selective read	0.000821

Naive vs Offset CCOL

Format	Read Time (s)	File Size (bytes)
Naive CCOL	0.001012	186
Offset CCOL	0.002051	248

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📂 Project Tree Structure

sql-mini-engine/
│   README.md
│   requirements.txt
│   LICENSE
│   .gitignore
│
├── data/
│   people.csv
│   people.ccol
│   people_naive.ccol
│   people_offsets.ccol
│   sales.csv
│
├── screenshots/
│   benchmarks.png
│   cli.png
│   tests.png
│   structure.png
│
├── sqlmini/
│   cli.py
│   engine.py
│   errors.py
│   parser.py
│   reader.py
│   writer.py
│   __init__.py
│
└── tests/
    test_parser.py
    test_engine.py
    test_performance.py
    test_ccol_bench.py
    test_selective_read_bench.py
    test_offsets_bench.py

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📸 Proof Screenshots

✅ CLI Query Run

✅ Pytest All Tests Passed

✅ Benchmark Outputs

✅ Project Tree Structure

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✅ Final Checklist

• Parser implemented
• Engine implemented
• CLI implemented
• Tests passing
• Benchmarks documented
• CCOL Writer/Reader implemented
• Selective reads working
• String offsets optimization verified
• README polished with proof screenshots
• Installation section added
• Extra query examples added
• LICENSE file included
• Root .gitignore included

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📄 License

This project is licensed under the MIT License — see the LICENSE file for details.

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