Relational Database Storage

Want to go straight to the reference documentation? Find it here.

MySQL functions are available in the spin_sdk::mysql module, and PostgreSQL functions in the spin_sdk::pg module. The function names match the operations above. This example shows MySQL:

// For PostgreSQL, use `spin_sdk::pg` or `spin_sdk::pg3`
use spin_sdk::mysql::{self, Connection, Decode, ParameterValue};

let connection = Connection::open(&address)?;

let params = vec![ParameterValue::Int32(id)];
// For PostgreSQL, use `$1` placeholder syntax
let rowset = connection.query("SELECT id, name FROM pets WHERE id = ?", &params)?;

match rowset.rows.first() {
    None => /* no rows matched query */,
    Some(row) => {
        let name = String::decode(&row[1])?;
    }
}

Notes

• Parameters are instances of the ParameterValue enum; you must wrap raw values in this type.
• A row is a vector of the DbValue enum. Use the Decode trait to access conversions to common types.
• Using PostgreSQL works in the same way, except that you use the spin_sdk::pg module instead of spin_sdk::mysql.
• Modified row counts are returned as u64. (MySQL execute does not return the modified row count.)
• All functions wrap the return in anyhow::Result.

You can find complete examples for using relational databases in the Spin repository on GitHub (MySQL, PostgreSQL).

For full information about the MySQL and PostgreSQL APIs, see the Spin SDK reference documentation.

Want to go straight to the reference documentation? Find it here.

The code below is an Outbound MySQL example. There is also an outbound PostgreSQL example available.

import { ResponseBuilder, Mysql } from '@fermyon/spin-sdk';

// Connects as the root user without a password 
const DB_URL = "mysql://root:@127.0.0.1/spin_dev"

/*
 Run the following commands to setup the instance:
 create database spin_dev;
 use spin_dev;
 create table test(id int, val int);
 insert into test values (4,4);
*/

export async function handler(_req: Request, res: ResponseBuilder) {
  // For PostgreSQL, use `Postgres.open`
  let conn = Mysql.open(DB_URL);
  // For PostgreSQL, use `$1` placeholder syntax
  conn.execute('delete from test where id=?', [4]);
  conn.execute('insert into test values (4,5)', []);
  let ret = conn.query('select * from test', []);
  // return a object that looks like 
  // { "columns": [{name: "id", dataType: "int32"}], "rows": [{ "id": 4, "val": 5 }] }
  res.send(JSON.stringify(ret, null, 2));
}

Want to go straight to the reference documentation? Find it here.

The code below is an Outbound MySQL example. There is also an outbound PostgreSQL example available.

from spin_sdk import http
from spin_sdk.http import Request, Response
from spin_sdk import mysql

class IncomingHandler(http.IncomingHandler):
    def handle_request(self, request: Request) -> Response:
        with mysql.open("mysql://root:@127.0.0.1/spin_dev") as db:
            print(db.query("select * from test", []))
        
        return Response(
            200,
            {"content-type": "text/plain"},
            bytes("Hello from Python!", "utf-8")
        )

Want to go straight to the reference documentation? Find it here.

MySQL functions are available in the github.com/fermyon/spin/sdk/go/v2/mysql package, and PostgreSQL in github.com/fermyon/spin/sdk/go/v2/pg. See Go Packages for reference documentation.

The package follows the usual Go database API. Use Open to return a connection to the database of type *sql.DB - see the Go standard library documentation for usage information. For example:

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"

	spinhttp "github.com/fermyon/spin/sdk/go/v2/http"
	"github.com/fermyon/spin/sdk/go/v2/pg"
)

type Pet struct {
	ID        int64
	Name      string
	Prey      *string // nullable field must be a pointer
	IsFinicky bool
}

func init() {
	spinhttp.Handle(func(w http.ResponseWriter, r *http.Request) {

		// addr is the environment variable set in `spin.toml` that points to the
		// address of the Mysql server.
		addr := os.Getenv("DB_URL")

		// For MySQL, use `mysql.Open`
		db := pg.Open(addr)
		defer db.Close()

		// For MySQL, use `?` placeholder syntax
		_, err := db.Query("INSERT INTO pets VALUES ($1, 'Maya', $2, $3);", int32(4), "bananas", true)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		rows, err := db.Query("SELECT * FROM pets")
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		var pets []*Pet
		for rows.Next() {
			var pet Pet
			if err := rows.Scan(&pet.ID, &pet.Name, &pet.Prey, &pet.IsFinicky); err != nil {
				fmt.Println(err)
			}
			pets = append(pets, &pet)
		}
		json.NewEncoder(w).Encode(pets)
	})
}

func main() {}