Add uuid to mysql

[videni]

I want to implement UUID for mysql using UUID_TO_BIN and BIN_TO_UUID as this article suggests. how to call the two sql functions please?

insert

UUID_TO_BIN to transform uuid:Uuid

Select

BIN_TO_UUID to transform uuid:Uuid

Here is an example writtern for sqlite, I made a few modifications, it is not tested, for I don't find any resource about how to specify UUID_TO_BIN and BIN_TO_UUID.

use std::io::Write;
use diesel::backend::Backend;
use diesel::deserialize;
use diesel::deserialize::FromSql;
use diesel::serialize;
use diesel::serialize::Output;
use diesel::sql_types::Binary;
use diesel::sql_types::HasSqlType;
use diesel::types::ToSql;
use diesel::mysql::Mysql;
use uuid::Uuid;

#[derive(Debug, AsExpression, FromSqlRow, Copy, Clone)]
pub struct UUID(Uuid);

impl<DB: Backend + HasSqlType<Binary>> ToSql<Binary, DB> for UUID {
    fn to_sql<W: Write>(&self, out: &mut Output<W, DB>) -> serialize::Result {
        let bytes = self.0.as_bytes();
        <[u8] as ToSql<Binary, DB>>::to_sql(bytes, out)
    }
}

impl FromSql<Binary, Mysql> for UUID {
    fn from_sql(bytes: Option<&<Mysql as Backend>::RawValue>) -> deserialize::Result<Self> {
        let bytes_vec: Vec<u8> = <Vec<u8> as FromSql<Binary, Mysql>>::from_sql(bytes)?;
        Ok(Uuid(Uuid::from_bytes(&bytes_vec)?))
    }
}

[weiznich]

UUID_TO_BIN and BIN_TO_UUID can be defined via sql_function!/no_arg_sql_function! in any third party crate.

[videni]

thanks, how can I call them in from_sql and to_sql ? Sorry , I am very new to rust, and diesel.

[weiznich]

To be clear: You cannot use UUID_TO_BIN or BIN_TO_UUID as part of your FromSql and ToSql implementations. Both implementations run on values already received from the database or on values on rust side before you send something to the database. They cannot invoke any database provided function like UUID_TO_BIN/BIN_TO_UUID. Those functions needs to be invoked explicitly as part of your query.