axumstart_db_macros 0.1.2

Proc macro powering axumstart_db's #[repository], SqlxInsert, and SqlxUpdate
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//! Compile-time backend selection. Exactly one of the crate's `postgres`/`mysql`/`sqlite`
//! features is enabled by the downstream consumer (mirrored automatically from
//! `axumstart_db`'s own features — see its `Cargo.toml`). These helpers decide the few
//! things that must be baked into generated SQL at macro-expansion time: placeholder
//! syntax, RETURNING availability, and a couple of dialect-specific SQL keywords.
//! Everything else (types, week-boundary SQL) is resolved at the call site via
//! `::axumstart_db::...` token paths instead, so this module stays small.

pub fn placeholder(idx: usize) -> String {
    if cfg!(feature = "postgres") {
        format!("${idx}")
    } else {
        "?".to_string()
    }
}

/// Postgres and SQLite both support `RETURNING *` (including after `ON CONFLICT`).
/// MySQL has no RETURNING at all — callers emulate it with a follow-up SELECT
/// (see `insert.rs`/`update.rs`'s `is_mysql()` branches).
pub fn is_mysql() -> bool {
    cfg!(feature = "mysql")
}

pub fn random_order_sql() -> &'static str {
    if cfg!(feature = "mysql") { "ORDER BY RAND()" } else { "ORDER BY RANDOM()" }
}