What are some alternatives?
When comparing PostgreSQL and Oracle DBaaS, you can also consider the following products
MySQL - The world's most popular open source database
SQLite - SQLite Home Page
Oracle Database 12c - Simplify database management and automate the information lifecycle with maximum security.
MariaDB - An enhanced, drop-in replacement for MySQL
MongoDB - MongoDB (from "humongous") is a scalable, high-performance, open source NoSQL database.
DB2 - IBM Db2 is database software that can reliably handle multiple workloads and the latest version of Db2 is optimized to provide extreme performance while lowering costs.