Re: PostgreSql Doubts

​Abandon trying to use PostgreSQL if you need an embedded SQL language. I, personally, would suggest either SQLite (https://www.sqlite.org) or FireBird SQL (www.firebirdsql.org). 

SQLite uses SQL which rather easy, but with its own peculiarities. It's main excellence is that it is indeed "lite" as in "not adding a lot of code to your project". The author is brilliant and takes a _very_ active role in supporting it. The license is basically "do whatever you want with the code" because he's donated to the "Public Domain" (not copyrighted it in any way). You can use it on Linux, Windows, and Mac OSX.

I don't know much about FireBird. I (not a lawyer) think it has a very good license. One interesting thing is that it says that it can run as a "server", like PostgreSQL, or "embedded", like SQLite. But I can't really figure out how the "embedded" is actually "embedded". 

Personally, despite some strange details (such as not enforcing data types, e.g. you can INSERT a string value into a column defined as NUMERIC), I think that SQLite is likely your best option. If you go to the web page mentioned previously and sign up for the "sqlite-users" forum, you'll get a good idea of how community minded the people using SQLite are. I think there are some very intelligent, articulate, and _nice_ people over there (unlike some forums I've been on).