Discover the Power of Lovefield a JavaScript Relational Database for Web Applications

Introduction to Lovefield

Lovefield is an open-source JavaScript library developed by Google, providing a powerful relational database for web applications. It allows developers to efficiently manage and query data in the browser, offering a SQL-like API. Below, we will explore some of the most useful APIs Lovefield offers, accompanied by code snippets and a sample application.

Connecting to a Database

  const lf = require('lovefield');
  const schemaBuilder = lf.schema.create('exampleDB', 1);

Schema Definition

  schemaBuilder.createTable('Employee')
    .addColumn('id', lf.Type.INTEGER)
    .addColumn('name', lf.Type.STRING)
    .addColumn('age', lf.Type.INTEGER)
    .addPrimaryKey(['id']);

Inserting Data

  const db = await schemaBuilder.connect();
  const emp = db.getSchema().table('Employee');
  
  const row = emp.createRow({
    'id': 1,
    'name': 'John Doe',
    'age': 30
  });
  
  await db.insert().into(emp).values([row]).exec();

Querying Data

  const results = await db.select().from(emp).where(emp.id.eq(1)).exec();
  console.log(results);

Updating Data

  await db.update(emp)
    .set(emp.name, 'Jane Doe')
    .where(emp.id.eq(1))
    .exec();

Deleting Data

  await db.delete().from(emp).where(emp.id.eq(1)).exec();
  console.log('Record deleted.');

Sample Application

Below is a simple example that demonstrates how these APIs can be used together in a comprehensive web application.

  (async () => {
    const lf = require('lovefield');
    const schemaBuilder = lf.schema.create('exampleApp', 1);
    
    schemaBuilder.createTable('Employee')
      .addColumn('id', lf.Type.INTEGER)
      .addColumn('name', lf.Type.STRING)
      .addColumn('age', lf.Type.INTEGER)
      .addPrimaryKey(['id']);
    
    const db = await schemaBuilder.connect();
    const emp = db.getSchema().table('Employee');
    
    const row = emp.createRow({
      'id': 1,
      'name': 'John Doe',
      'age': 30
    });
    
    await db.insert().into(emp).values([row]).exec();
    
    let results = await db.select().from(emp).where(emp.id.eq(1)).exec();
    console.log(results);
    
    await db.update(emp)
      .set(emp.name, 'Jane Doe')
      .where(emp.id.eq(1))
      .exec();
    
    results = await db.select().from(emp).exec();
    console.log(results);
    
    await db.delete().from(emp).where(emp.id.eq(1)).exec();
    console.log('Record deleted.');
    
  })();

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