There are many ways of getting the data out of a database. Some are PostgreSQL specific, some are PostGIS specific. The point is that you can use and mix any tools you prefer. There will be scenarios where simple data extraction procedures will do just fine; some other cases will require a more specialized setup, SQL or psql, or even writing custom code in external languages. I do hope this chapter gives you a toolset you can use with confidence in your daily activities.
We have not touched upon exposing the data through web services - another chapter is fully devoted to this topic, so stay tuned.