vityafx / diesel-chrono-duration

Adds chrono duration support for the diesel ORM

diesel-chrono-duration

This crate adds support for the chrono::Duration type into the diesel ORM.

Why

Diesel crate has a policy of including only such type implementations which can be represented as is in the SQL types. chrono::Duration does not have a direct 1-to-1 mapping in both the SQLite and PostgreSQL.

How

The chrono::Duration type stores its value as i64 number. This is exactly 8 bytes and such types are BigInteger and BigInt. So, the ToSql and FromSql traits implementation simply uses chrono::Duration's inner i64 value.

Usage

To implement this we added ChronoDurationProxy type which is just a strong type as defined as:

pub struct ChronoDurationProxy(pub chrono::Duration);

In your table model you use it instead of chrono::Duration:

extern crate diesel_chrono_duration;

use diesel_chrono_duration::ChronoDurationProxy;

#[derive(Debug, Clone, Queryable, Insertable)]
#[table_name = "sometable"]
pub struct SomeTable {
    /// The ID of the record in the table.
    pub id: i32,
    /// Some duration
    pub duration: ChronoDurationProxy,
}

Later, when you want to use it's value as chrono::Duration you have these options:

• *duration returns a reference to the inner chrono::Duration object. It is done by the Deref trait.
• &duration also returns a reference to the inner chrono::Duration object. It is done by the AsRef trait.
• duration.0 as in usual rust.

Contribute

The project is very simple and small but all contributions are "please make a contribution". Thanks in advance.

License

This project is licensed under the MIT license.

diesel-chrono-duration's Issues

Documentation sould have a working example

Now it ends with extern crate line.