What are some alternatives?
SQLite - SQLite Home Page
MySQL - The world's most popular open source database
MongoDB - MongoDB (from "humongous") is a scalable, high-performance, open source NoSQL database.
Microsoft SQL Server - Microsoft Azure is an open, flexible, enterprise-grade cloud computing platform. Move faster, do more, and save money with IaaS + PaaS. Try for FREE.
Oracle Database - Discover the world's #1 database and cloud database management products and solutions including the self-driving and fully automated Autonomous Database Cloud 18c.
MariaDB - An enhanced, drop-in replacement for MySQL