code-boxx/0-JS-SQLITE.MD

## 0-JS-SQLITE.MD

      
    Raw
  

              0-JS-SQLITE.MD
            
          
    JAVASCRIPT SQLITE

https://code-boxx.com/sqlite-javascript/
LICENSE

Copyright by Code Boxx
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

  
## sqljs.html
<!DOCTYPE html>
<html>
  <head>
    <!-- https://cdnjs.com/libraries/sql.js -->
    <!-- https://github.com/sql-js/sql.js -->
    <title>Javascript SQLite</title>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.8.0/sql-wasm.js"></script>
    <script src="sqljs.js"></script>
  </head>
  <body>
  </body>
</html>

## sqljs.js
var demo = {
  // (A) INITIALIZE
  db     : null,           // database object
  cache  : null,           // storage cache object
  cname  : "SQLDB",        // cache storage name
  dbname : "/demo.sqlite", // database storage name
  init : async () => {
    // (A1) STORAGE CACHE + SQLJS
    demo.cache = await caches.open(demo.cname);
    const SQL = await initSqlJs({
      locateFile: filename => `https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.8.0/${filename}`
    });

    // (A2) ATTEMPT TO LOAD DATABASE FROM STORAGE CACHE
    demo.cache.match(demo.dbname).then(async r => {
      // (A2-1) NOT FOUND - CREATE A NEW DATABASE
      if (r==undefined) {
        demo.db = new SQL.Database();
        demo.db.run(`CREATE TABLE events (
          id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
          date TEXT NOT NULL,
          text TEXT NOT NULL
        )`);
        demo.db.run("CREATE INDEX date ON events (date)");
        await demo.export();
        await demo.run();
        demo.get();
      }

      // (A2-2) LOAD EXISTING DATABASE
      else {
        const buf = await r.arrayBuffer();
        demo.db = new SQL.Database(new Uint8Array(buf));
        demo.get();
      }
    });
  },

  // (B) EXPORT TO CACHE STORAGE
  export : async () => await demo.cache.put(
    demo.dbname, new Response(demo.db.export())
  ),

  // (C) DEMO - INSERT/UPDATE EVENT
  run : async () => {
    // (C1) INSERT
    demo.db.run(
      `INSERT INTO events (date, text) VALUES (?,?), (?,?), (?,?)`, [
      "2077-06-05 00:00:00", "First event.",
      "2077-06-06 00:00:00", "Second event.",
      "2077-06-07 00:00:00", "Third event."
    ]);

    // (C2) UPDATE
    demo.db.run(
      `UPDATE events SET date=?, text=? WHERE id=?`,
      ["2077-06-06 00:00:00", "Second event EDITED.", 2]
    );

    // (C3) DELETE
    demo.db.run("DELETE FROM events WHERE id=?", [1]);

    // (C4) "COMMIT"
    await demo.export();
  },

  // (D) DEMO - GET EVENT
  get : () => {
    // (D1) GET SINGLE ENTRY
    let stmt = demo.db.prepare("SELECT * FROM events WHERE id=$id"),
        res = stmt.getAsObject({$id:2});
    console.log(res);

    // (D2) GET MULTIPLE ENTRIES
    stmt = demo.db.prepare(
      `SELECT * FROM events
       WHERE date BETWEEN $start AND $end`);
    stmt.bind({$start:"2077-06-01 00:00:00", $end:"2077-06-08 00:00:00"})
    while (stmt.step()) {
      res = stmt.getAsObject();
      console.log(res);
    }
  }
};

// (E) GO!
window.addEventListener("load", demo.init);
	<!DOCTYPE html>
	<html>
	<head>
	<!-- https://cdnjs.com/libraries/sql.js -->
	<!-- https://github.com/sql-js/sql.js -->
	<title>Javascript SQLite</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.8.0/sql-wasm.js"></script>
	<script src="sqljs.js"></script>
	</head>
	<body>
	</body>
	</html>
	var demo = {
	// (A) INITIALIZE
	db : null, // database object
	cache : null, // storage cache object
	cname : "SQLDB", // cache storage name
	dbname : "/demo.sqlite", // database storage name
	init : async () => {
	// (A1) STORAGE CACHE + SQLJS
	demo.cache = await caches.open(demo.cname);
	const SQL = await initSqlJs({
	locateFile: filename => `https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.8.0/${filename}`
	});

	// (A2) ATTEMPT TO LOAD DATABASE FROM STORAGE CACHE
	demo.cache.match(demo.dbname).then(async r => {
	// (A2-1) NOT FOUND - CREATE A NEW DATABASE
	if (r==undefined) {
	demo.db = new SQL.Database();
	demo.db.run(`CREATE TABLE events (
	id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
	date TEXT NOT NULL,
	text TEXT NOT NULL
	)`);
	demo.db.run("CREATE INDEX date ON events (date)");
	await demo.export();
	await demo.run();
	demo.get();
	}

	// (A2-2) LOAD EXISTING DATABASE
	else {
	const buf = await r.arrayBuffer();
	demo.db = new SQL.Database(new Uint8Array(buf));
	demo.get();
	}
	});
	},

	// (B) EXPORT TO CACHE STORAGE
	export : async () => await demo.cache.put(
	demo.dbname, new Response(demo.db.export())
	),

	// (C) DEMO - INSERT/UPDATE EVENT
	run : async () => {
	// (C1) INSERT
	demo.db.run(
	`INSERT INTO events (date, text) VALUES (?,?), (?,?), (?,?)`, [
	"2077-06-05 00:00:00", "First event.",
	"2077-06-06 00:00:00", "Second event.",
	"2077-06-07 00:00:00", "Third event."
	]);

	// (C2) UPDATE
	demo.db.run(
	`UPDATE events SET date=?, text=? WHERE id=?`,
	["2077-06-06 00:00:00", "Second event EDITED.", 2]
	);

	// (C3) DELETE
	demo.db.run("DELETE FROM events WHERE id=?", [1]);

	// (C4) "COMMIT"
	await demo.export();
	},

	// (D) DEMO - GET EVENT
	get : () => {
	// (D1) GET SINGLE ENTRY
	let stmt = demo.db.prepare("SELECT * FROM events WHERE id=$id"),
	res = stmt.getAsObject({$id:2});
	console.log(res);

	// (D2) GET MULTIPLE ENTRIES
	stmt = demo.db.prepare(
	`SELECT * FROM events
	WHERE date BETWEEN $start AND $end`);
	stmt.bind({$start:"2077-06-01 00:00:00", $end:"2077-06-08 00:00:00"})
	while (stmt.step()) {
	res = stmt.getAsObject();
	console.log(res);
	}
	}
	};

	// (E) GO!
	window.addEventListener("load", demo.init);