About

This repository contains the codebase of my DBMS project named Mini SQL Engine. Mini SQL Engine is written in Python and can parse and execute a subset of DML queries given using the command-line interface on data stored as CSV files. Please Read problem_description.pdf for more details.

Following cases of query processing are handled as of now.

• Blank column entries while entering data
• Single and double quoted values in CSV files
• Multiple AND/OR queries, including nested ones
• Operators handled in column comparison: =, !=, >, <, <=, >=
• Aggregate functions: distinct, sum, min, max, avg.
• Pretty Table output
• Summary of successful query
• Table aliasing

Requirements

• Python 2.7
• SQL Parse (pip install sqlparse)
• Pretty Table (pip install prettytable)

Files

• mini_sql.py: Main File
• sample_data: It contains two sample data inside folders A and B for testing purpose.
• instructions.md: Instructions to run sql query
• metadata.txt: Contains metadata: table and column names
• table1.csv: It contains data of table named "table1"

NOTE:

1. Column name should not start with number but can contain a table name.
2. The case of the DML language (query) does not matter.
3. When selection from multiple tables is made, the user will expect to give an equijoin condition; otherwise, it would perform cross-join and output the result accordingly.
4. In case of multiple AND/OR, the conditions must be properly enclosed within ().