retrieving postgres `date` type without chrono

[djanatyn]

Today while pair-programming, we had a postgres database with a date column. We were trying to use postgres::row::Row#get with postgres::types::Date:

/// A wrapper that can be used to represent infinity with `Type::Date` types.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Date<T> {
    /// Represents `infinity`, a date that is later than all other dates.
    PosInfinity,
    /// Represents `-infinity`, a date that is earlier than all other dates.
    NegInfinity,
    /// The wrapped date.
    Value(T),
}

At first we were confused by what T should be, and tried i32:

let a: postgres::types::Date<i32> = row.get("date");

That didn't end up working (sorry, don't have the error message), so we switched to using the with-chrono-0_4 feature, and returned chrono::NaiveDate instead:

let date: chrono::NaiveDate = row.get("date");

I was wondering:

• Is it possible to use postgres::types::Date with the postgres date type in this context? I couldn't find any examples of usage, or any associated tests.
• If you can use postgres::types::Date, what is the meaning of the <T> parameter? For a regular postgres date column, what should T be?

Thank you for your time!

[sfackler]

postgres::types::Date<chrono::NaiveDate>.

The date enum handles the infinity values that Postgres supports but Rust date types typically do not. If you aren't using infinite date values in your database you should just use chrono::NaiveDate directly.

[djanatyn]

Thank you, that explains it!