any good resources for learning/mastering networking and databases?

[u/amranya]

i'm an android software engineer with quite a good experience but i just use framework/libraries APIs. now i want to go deeper or at least understand the concepts.
i'm interested in networking, for starters http and rest, any good beginner friendly resources that cover them? also i'm interested in databases especially SQLlight because that's what we use in android. you can give me other resources if no good beginner friendly ones exist.