Web SQL is a web technology, not a standard SQL database system like MySQL or SQL Server, but it relates to SQL in the context of client-side storage in web browsers.

What is Web SQL?

• Web SQL Database is an API that allows web applications to store data locally in a browser using a SQL-based relational database.

• It uses SQLite as the underlying database engine.

• Allows executing SQL queries (like SELECT, INSERT, UPDATE, etc.) directly from JavaScript.

• Meant for offline storage or caching data in web apps.

Key Points

• Introduced as part of HTML5 specs but deprecated and not recommended for new projects.

• Not supported by all browsers — primarily Chrome, Opera, and Safari supported it; Firefox and Edge do not.

• Replaced by newer technologies like IndexedDB for client-side storage.

Basic Example of Web SQL Usage (JavaScript)

var db = openDatabase('mydb', '1.0', 'Test DB', 2 * 1024 * 1024);db.transaction(function (tx) {  tx.executeSql('CREATE TABLE IF NOT EXISTS employees (id unique, name)');  tx.executeSql('INSERT INTO employees (id, name) VALUES (1, "Alice")');  tx.executeSql('SELECT * FROM employees', [], function (tx, results) {    var len = results.rows.length, i;    for (i = 0; i < len; i++){      console.log(results.rows.item(i).name);    }  });});

Summary

If you want, I can explain alternatives for client-side storage or how to work with IndexedDB!