Welcome to PostgreSQL and the PostgreSQL Tutorial. The following few chapters are intended to give a simple introduction to PostgreSQL, relational database concepts, and the SQL language to those who are new to any one of these aspects. We only assume some general knowledge about how to use computers. No particular Unix or programming experience is required. This book is mainly intended to give you a hands-on experience with important aspects of the PostgreSQL system. It makes no attempt to be a complete or thorough treatment of the topics it covers.
After you have worked through this tutorial you might want to move on to reading the PostgreSQL 7.3.21 User's Guide to gain a more formal knowledge of the SQL language, or the PostgreSQL 7.3.21 Programmer's Guide for information about developing applications for PostgreSQL. Those who set up and manage their own server should also read the PostgreSQL 7.3.21 Administrator's Guide.
Read the upstream documentation. For corrections, first check the current manual.