What is the relationship/difference between Decode, sqlx::Type

[finlaydotb]

There are two traits that currently leaves me confuse. I am particular not sure in what scenario to implement them, and what is their actual use. These two traits are

sqlx::decode::Decode: See https://docs.rs/sqlx/latest/sqlx/decode/trait.Decode.html
and
sqlx::Type: see https://docs.rs/sqlx/latest/sqlx/trait.Type.html

I would appreciate some explanation.

When are these traits needed? How do they relate with the query_as! macros? Do they compliment each other?