Rust enum to sql integer how to ?

[sackery]

No description provided.

[weiznich]

There is #429 open, which add support for adding custom type mapping. This could be used to map an enum to an integer.
@sgrif stated in #483 he is not sure if he want to add support for this in diesel. I've extracted the corresponding code here so it could be used without landing this pull-request. (If needed I could also upload it to crates.io)

[killercup]

FYI tracking issue for Postgres' custom enum types is #343

[quadrupleslap]

Pointing out the obvious, it's easy to cast it into an integer with as and match it back if you wanted to, but that removes the guarantee that values always represent the variants of the enum.

[dbrgn]

I'd also like to request some documentation on this issue. I managed to implement FromSqlRow for a String based enum with the help from #429, but I can't get AsExpression working.

[dbrgn]

Finally got AsExpression to work: https://gist.github.com/dbrgn/9e88f54e23b4640bb3641734277a85dd

[sgrif]

You can also see how we're handling this in crates.io -- https://github.com/rust-lang/crates.io/blob/4082d4e49c0e24a4883f301cc299360d4b828aaf/src/dependency.rs#L162-L184 https://github.com/rust-lang/crates.io/blob/4082d4e49c0e24a4883f301cc299360d4b828aaf/src/dependency.rs#L54-L65

[sgrif]

Closing for the same reasons as #343 (comment)