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GitHub - nerbrain/sqlalt

SQL Alt (Alternative)

A lightweight SQL database implementation written in Go. SQLalt provides a command-line interface to create tables, insert data, and query results with basic SQL syntax support.

Features

  • Create Tables - Define tables with custom columns and data types
  • Insert Data - Add rows to tables with constraint validation
  • Select Data - Query tables with WHERE clause filtering and column selection
  • Persistent Storage - Data is automatically saved to JSON files
  • Interactive CLI - User-friendly command-line prompt for executing SQL commands
  • Data Validation - Support for NOT NULL, UNIQUE, and PRIMARY KEY constraints

Installation

git clone https://github.com/nerbrain/sqlalt.git
cd sqlalt
go build

Usage

Start the interactive prompt:

Creating a Table

CREATE TABLE users (id INT PRIMARY KEY, name STRING NOT NULL, email STRING UNIQUE)

Show all Tables

Inserting Data

INSERT INTO users (id, name, email) VALUES ('1', 'john', 'john@example.com')
INSERT INTO users (id, name, email) VALUES ('2', 'jane', 'jane@example.com')

Selecting Data

Select all rows:

Select specific columns:

SELECT id, name FROM users

Select with WHERE clause:

SELECT * FROM users WHERE id = '1'

Commands

  • .quit or .exit - Exit the program
  • Any other input starting with . - Shows an error for unrecognized commands

Data Storage

Tables and data are stored as JSON files in the specific database directory called data.

Supported Data Types

  • INT - Integer values
  • STRING - Text values
  • FLOAT - Decimal numbers
  • BOOL - Boolean values

Constraints

  • PRIMARY KEY - Uniquely identifies each row
  • UNIQUE - Ensures column values are unique
  • NOT NULL - Column cannot have null values

Future Enhancements

  • UPDATE and DELETE statements
  • JOINs between tables
  • ORDER BY and GROUP BY clauses
  • Index optimization
  • Transaction support

Sources used for this project