Schema Spelunker

An interactive desktop tool for exploring database schemas — fast, native, GPU-accelerated, and built in the handmade spirit.

Inspired by SchemaSpy and its wonderful diagramming, but aiming for a live, interactive experience rather than static HTML output.

Vision

Open a database file in a GUI and immediately see its schema
ER diagrams rendered interactively — zoom, pan, select, explore
Sub-diagrams showing 1–2 degrees of separation from a selected table
Everything stays fast because it runs natively on the GPU
Dump the schema to a custom snapshot format so you can explore offline without repeatedly hitting the database
CLI mode (schema_spelunker path/to/database.db) for scripting and CI

Philosophy

Handmade software in the spirit of Casey Muratori, Ryan Fleury, and gingerBill: minimal dependencies, own the stack where it counts, no framework magic. The project uses Odin for its no-nonsense approach to systems programming and its excellent FFI for binding C libraries like SQLite.

Current status

Early but building fast.

SQLite: vendored as source (vendor/sqlite3/sqlite3.c amalgamation v3.48.0) instead of a binary .dll. Compiled to a static .lib on the first build. Schema introspection via PRAGMA table_info and PRAGMA foreign_key_list works on the command line.

GUI: Dear ImGui v1.92.8-docking with full C-ABI bindings via dear_bindings-generated dcimgui + Capati/odin-imgui Odin bindings. rlImGui bridges raylib (windowing, input, rendering) to ImGui. ImNodes (nelarius/imnodes) is vendored and bound for the ER diagram node graph. Docking is enabled.

Build: all native dependencies (SQLite, ImGui, ImNodes, rlImGui) are compiled from source on the first build using MSVC, auto-detected via vswhere. No binary blobs in the repo. Subsequent builds are pure-Odin and take under a second.

Building & running

Requires MSVC (Visual Studio 2022 Build Tools or newer) on Windows. The build script auto-detects your VS installation via vswhere.

build.bat              # debug build (compiles native libs on first run)
build.bat run          # debug build + run
build.bat release      # optimized build
build.bat clean        # remove build output

The spelunker takes a database path as a CLI argument:

schema_spelunker.exe path/to/database.db

Running without arguments opens the GUI.

Seeding a test database

A sample multi-tenant Kanban board schema is in test/complex.sql with 16 tables, users, teams, roles, permissions, boards, columns, cards, labels, comments, and activity history.

seed.bat                         # creates seed.db from test/complex.sql
schema_spelunker.exe seed.db     # explore it via CLI
build.bat run                    # explore it via GUI

Architecture

vendor/
├── sqlite3/
│   ├── sqlite3.c / .h          SQLite amalgamation (compiled to .lib)
│   └── sqlite3.odin            Odin FFI bindings
├── imgui/
│   ├── imgui.cpp / .h etc.     ImGui v1.92.8-docking source
│   ├── dcimgui.h / .cpp        dear_bindings C wrapper (extern "C")
│   ├── imgui.odin              Odin bindings from Capati/odin-imgui
│   ├── imnodes.cpp / .h        ImNodes source
│   ├── dcimnodes.h / .cpp      Hand-written ImNodes C wrapper
│   └── imnodes.odin            Hand-written ImNodes Odin bindings
└── rlimgui/
    ├── rlImGui.cpp / .h        raylib→ImGui backend
    ├── rlImGui.odin            Odin bindings
    └── include/                raylib C headers (v6.0) for compilation

All C/C++ sources are compiled into a single static .lib by _compile_libs.bat when any of the .lib files are missing. Odin then links against these via foreign import.