docs: add a Databases guide hub under Guides

runtime/_data.ts

@@ -65,6 +65,10 @@ export const sidebar = [
         title: "HTTP Server",
         href: "/runtime/fundamentals/http_server/",
       },
+      {
+        title: "Databases",
+        href: "/runtime/databases/",
+      },
       {
         title: "Testing",
         href: "/runtime/test/",

runtime/databases/index.md

@@ -0,0 +1,136 @@
+---
+last_modified: 2026-06-16
+title: "Databases"
+description: "Use databases with Deno: the built-in node:sqlite and Deno KV, plus Postgres, MySQL, MongoDB, and Redis through the same npm drivers you use in Node.js."
+---
+
+Deno ships two databases inside the runtime, with nothing to install:
+
+- **`node:sqlite`** — a built-in SQLite module (added in Deno 2.2).
+- **Deno KV** — a built-in key-value store that needs zero configuration on
+  [Deno Deploy](/deploy/).
+
+For every other database — Postgres, MySQL, MongoDB, Redis, and the rest — you
+use the **same npm driver you would in Node.js**. Deno reads npm packages
+directly through [Node.js compatibility](/runtime/fundamentals/node/), so the
+connection code is identical to a Node project: import the driver and connect.
+
+## SQLite, built in
+
+SQLite runs in-process with no server and no dependency to add. Import
+`DatabaseSync` from `node:sqlite`, open a file, and run SQL:
+
+```ts title="main.ts"
+import { DatabaseSync } from "node:sqlite";
+
+// Open (or create) a database file
+const db = new DatabaseSync("test.db");
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS people (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name TEXT,
+    age INTEGER
+  );
+`);
+
+// Insert a row with bound parameters
+db.prepare("INSERT INTO people (name, age) VALUES (?, ?);").run("Bob", 40);
+
+// Query it back
+const rows = db.prepare("SELECT id, name, age FROM people").all();
+console.log(rows);
+
+db.close();
+```
+
+Because it reads and writes a file, run it with read and write permission:
+
+```sh
+deno run -R -W main.ts
+```
+
+See the [full SQLite example](/examples/sqlite/) for more operations.
+
+## Deno KV, built in
+
+[Deno KV](/deploy/kv/) is a key-value database built into the runtime. Open the
+default store with [`Deno.openKv()`](/api/deno/~/Deno.openKv); keys are arrays,
+so you can lay data out hierarchically and list by prefix:
+
+```ts title="main.ts"
+const kv = await Deno.openKv();
+
+// Store, then read back a single record
+await kv.set(["players", "alice"], { rank: "gold" });
+const alice = await kv.get(["players", "alice"]);
+console.log(alice.key, alice.value);
+
+// List every record under a key prefix, ordered lexicographically
+for await (const entry of kv.list({ prefix: ["players"] })) {
+  console.log(entry.key, entry.value);
+}
+
+await kv.delete(["players", "alice"]);
+```
+
+Deno KV is currently unstable, so run it with the `--unstable-kv` flag:
+
+```sh
+deno run --unstable-kv main.ts
+```
+
+It's a good fit for fast reads that don't need the query flexibility of SQL, and
+it works with zero configuration when you deploy to Deno Deploy. For atomic
+transactions, secondary indexes, and the full API, see the
+[Deno KV docs](/deploy/kv/) and the [Deno KV example](/examples/kv/).
+
+## Other databases (npm drivers)
+
+Any database with an npm driver works under Deno. Import the driver with an
+`npm:` specifier (or list it in `package.json`) and connect exactly as you would
+in Node.js. Keep connection settings in environment variables so the same code
+runs locally and in production. Here is Postgres with the `postgres` driver:
+
+```ts title="main.ts"
+import postgres from "npm:postgres";
+
+// Connection settings come from the standard PG* environment variables
+const sql = postgres();
+
+const people = await sql`SELECT id, name FROM people`;
+console.log(people);
+
+await sql.end();
+```
+
+This needs network and environment access (add `--env-file` if you keep the
+variables in a `.env` file):
+
+```sh
+deno run -N -E main.ts
+```
+
+The same pattern covers the rest. Each link below is a runnable example or a
+tutorial:
+
+- **Postgres** — [Connect to Postgres](/examples/postgres/), or
+  [Supabase](/examples/supabase/)
+- **MySQL** — [Use MySQL with Deno](/examples/mysql2_tutorial/), or
+  [PlanetScale](/examples/planetscale_tutorial/)
+- **MongoDB** — [Connect to MongoDB](/examples/mongo/), or
+  [Mongoose](/examples/mongoose_tutorial/)
+- **Redis** — [Redis quick start](/examples/redis/), or the
+  [Redis tutorial](/examples/redis_tutorial/)
+- **DuckDB** — [Connect to DuckDB](/examples/duckdb/)
+
+## ORMs
+
+ORMs that run on npm work the same way:
+
+- **Drizzle** — [Use Drizzle with Deno](/examples/drizzle_tutorial/)
+- **Prisma** — [Use Prisma with Deno](/examples/prisma_tutorial/)
+
+New to databases in Deno? The
+[Connecting to databases](/examples/connecting_to_databases_tutorial/) tutorial
+walks through the options above.