launchbadge/sqlx

Extend derive(FromRow) with additional features/attributes

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#156 opened on Mar 26, 2020

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 (2 comments) (19 reactions) (0 assignees)Rust (13,916 stars) (1,307 forks)batch import
E-mediumenhancementgood first issuehelp wanted

Description

  • Handle #[sqlx(rename = "new_name")] on a struct field

  • Support the derive on a tuple struct and use by ordinal retrieval from the row

  • Handle #[sqlx(ordinal = 3)] to use ordinal retrieval from the row ( row.get(3) )

  • Handle a field that is impl FromRow. A parallel from serde_json would perhaps make this #[sqlx(flatten)].

    #[derive(sqlx::FromRow)]
struct Bar {
    baz: i32  // row.get("baz")
 }

#[derive(sqlx::FromRow)]
struct Foo {
    foo: i32, // row.get("foo")
    #[sqlx(flatten)]
    bar: Bar
}

Contributor guide

Tech stack
rustsql
Domain
backenddatabasedeveloper experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust programmingProcedural macrosSQL row retrieval
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue requests adding `#[sqlx(ordinal = 3)]` and `#[sqlx(flatten)]` to the `FromRow` derive macro. Start by examining the existing derive macro code in `sqlx macros/src/lib.rs` to understand how attributes are parsed. For `flatten`, study how serde implements `#[serde(flatten)]` as a reference. Then implement the attribute handling and test with the provided struct examples.