About the Project

This is a finished Java implementation for the "Build Your Own SQLite" Challenge. This code implements functionality for all stages (and extentions) of the challenge as of 2025-02-22.

What can it do?

1. Print the page size and number of tables in a sqlite3 database via the .dbinfo command.
2. Print the names of tables in a sqlite3 database via .tables.
3. Do a simple COUNT(*) operation (./your_program.sh sample.db "select count(*) from apples").
4. Read data from a single column (./your_program.sh sample.db "SELECT name FROM apples").
5. Read data from multiple columns (./your_program.sh sample.db "SELECT name, color FROM apples").
6. Filter data with a WHERE clause (only supports = operator and only compares against TEXT or VARCHAR columns ./your_program.sh sample.db "SELECT name, color FROM apples WHERE color = 'Yellow'").
7. Retrieve data with a full-table scan ( ./your_program.sh superheroes.db "SELECT id, name FROM superheroes WHERE eye_color = 'Pink Eyes'").
8. Retrieve data using an index (given the index exists for the table and the query is checking for equality between a string and a single indexed column of type TEXT or VARCHAR).

Running Locally

You will need Java 23 (or later) and maven installed to run this code. The program can then be run with:

./your_program.sh sample.db <command>

Note that not all functionality can be demonstrated with the included sample.db (there is no index defined on any table).

Improvements

• Add more restrictive access modifiers and rearrange packages to enable that.
• Handle COUNT(*) more gracefully in the query package.

Test Run Video

A short video of the code being run in the codecrafters test environment:

codecrafters-sqlite-java-test-run-av1.webm