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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Web SQL UPDATE rowsAffected</title>
  <style>
    body { font-family: system-ui, sans-serif; margin: 1.5rem; line-height: 1.5; }
    button { margin-right: 0.5rem; margin-bottom: 0.5rem; padding: 0.5rem 0.9rem; cursor: pointer; }
    #status { margin-top: 1rem; }
  </style>
</head>
<body>
  <h1>Check rowsAffected</h1>
  <p>Seed id 1, then try updating id 1 vs id 99.</p>

  <button type="button" id="seedBtn" disabled>Seed id 1</button>
  <button type="button" id="upd1Btn" disabled>Update id 1</button>
  <button type="button" id="upd99Btn" disabled>Update id 99</button>

  <p id="status">Checking Web SQL&hellip;</p>

  <script>
    var statusEl = document.getElementById('status');

    if (!window.openDatabase) {
      statusEl.textContent = 'Web SQL is not available in this browser.';
    } else {
      var db = openDatabase('tryitWsqlUpdateRows', '1.0', 'Try It', 1024 * 1024);

      function updateName(id, name) {
        db.transaction(function (tx) {
          tx.executeSql(
            'UPDATE contacts SET name = ? WHERE id = ?',
            [name, id],
            function (tx, result) {
              if (result.rowsAffected === 0) {
                statusEl.textContent = 'No row with id ' + id + ' (rowsAffected = 0).';
              } else {
                statusEl.textContent = 'Updated id ' + id + ' (rowsAffected = ' + result.rowsAffected + ').';
              }
            }
          );
        });
      }

      db.transaction(function (tx) {
        tx.executeSql(
          'CREATE TABLE IF NOT EXISTS contacts (id INTEGER PRIMARY KEY, name TEXT)'
        );
      }, null, function () {
        statusEl.textContent = 'Ready.';
        document.getElementById('seedBtn').disabled = false;
        document.getElementById('upd1Btn').disabled = false;
        document.getElementById('upd99Btn').disabled = false;
      });

      document.getElementById('seedBtn').addEventListener('click', function () {
        db.transaction(function (tx) {
          tx.executeSql(
            'INSERT OR REPLACE INTO contacts (id, name) VALUES (?, ?)',
            [1, 'Original'],
            function () {
              statusEl.textContent = 'Seeded id 1.';
            }
          );
        });
      });

      document.getElementById('upd1Btn').addEventListener('click', function () {
        updateName(1, 'Changed');
      });

      document.getElementById('upd99Btn').addEventListener('click', function () {
        updateName(99, 'Missing');
      });
    }
  </script>
</body>
</html>
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Web SQL UPDATE — Check rowsAffected
