Add sqlite build and data spec

.github/workflows/ci.yml

@@ -53,6 +53,29 @@ jobs:
       - name: Run TCD validation tests
         run: npm run test -w tcd
 
+  sqlite:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: "24"
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Build project
+        run: npm run build
+
+      - name: Build SQLite database
+        run: npm run build -w sqlite
+
+      - name: Run SQLite validation tests
+        run: npm run test -w sqlite
+
   lint:
     runs-on: ubuntu-latest
     steps:

packages/sqlite/README.md

@@ -0,0 +1,70 @@
+# Neaps Tide Database - TideBase (SQLite)
+
+This package generates a [TideBase](./spec.md) file — an SQLite database containing all stations from the Neaps Tide Database with harmonic constituents, tidal datums, subordinate station offsets, and precomputed equilibrium arguments and node factors for tide prediction.
+
+TideBase is a modern, portable, and queryable database containing everything needed for tide prediction in an SQLite database.
+
+## Usage
+
+Download the latest `*.tidebase` file from [GitHub Releases](https://github.com/openwatersio/tide-database/releases) and query it with any SQLite client:
+
+```sh
+sqlite3 neaps*.tidebase
+```
+
+### Find a station
+
+```sql
+SELECT station_id, name, latitude, longitude
+FROM stations
+WHERE station_id = 'noaa/9414290';
+```
+
+### Find nearby stations
+
+```sql
+SELECT station_id, name, latitude, longitude
+FROM stations
+WHERE latitude BETWEEN 37.5 AND 38.0
+  AND longitude BETWEEN -122.6 AND -122.2
+ORDER BY name;
+```
+
+### Get prediction data for a station and year
+
+```sql
+SELECT sc.constituent, c.speed, sc.amplitude, sc.phase,
+  ea.value AS eq_argument, nf.value AS node_factor
+FROM station_constituents sc
+JOIN stations s ON s.id = sc.station_id
+JOIN constituents c ON c.name = sc.constituent
+LEFT JOIN equilibrium_arguments ea
+  ON ea.constituent = sc.constituent AND ea.year = 2026
+LEFT JOIN node_factors nf
+  ON nf.constituent = sc.constituent AND nf.year = 2026
+WHERE s.station_id = 'noaa/9414290'
+ORDER BY c.speed;
+```
+
+See [examples/](./examples/) for more queries. See [spec.md](./spec.md) for the full specification.
+
+## Contributing
+
+Build the database:
+
+```sh
+npm run build
+```
+
+### Testing
+
+The test suite validates that the built database correctly preserves all station data from the source JSON files, and that all example queries execute successfully.
+
+```sh
+npm test
+```
+
+## References
+
+- [TideBase Specification](./spec.md)
+- [@neaps/tide-predictor](https://github.com/openwatersio/neaps/tree/main/packages/tide-predictor)

packages/sqlite/build

@@ -0,0 +1,5 @@
+#!/bin/bash
+set -e
+cd "$(dirname "$0")"
+rm -rf dist && mkdir -p dist
+node build.ts