nautilus-dialect

SQL dialect renderers for the Nautilus ORM.

This crate translates query ASTs produced by nautilus-core into dialect-specific SQL strings with bound parameters ready for execution via nautilus-connector.

Supported dialects

Usage

use nautilus_dialect::{Dialect, PostgresDialect};
use nautilus_core::{Select, Value};

let select = Select::from_table("users")
    .filter(
        nautilus_core::Expr::column("email")
            .eq(nautilus_core::Expr::param(Value::String("alice@example.com".into())))
    )
    .build()?;

let sql = PostgresDialect.render_select(&select)?;
// sql.text   => SELECT * FROM "users" WHERE ("email" = $1)
// sql.params => [Value::String("alice@example.com")]

Architecture

The crate is organized as follows:

• lib.rs — Public API: Dialect trait, Sql struct, shared rendering macros (render_insert_body!, render_update_body!, render_delete_body!, render_select_body_core!, render_returning!), and shared render helpers for identifier writing and placeholder formatting.

• render_estimate.rs — Conservative SQL/params capacity estimation used by the dialect renderers to preallocate String and Vec<Value> buffers.

• postgres.rs — PostgreSQL renderer. Handles $N placeholders, DISTINCT ON, FILTER (WHERE ...) on aggregates, and @> / <@ / && array operators.

• mysql.rs — MySQL renderer. Uses ? placeholders and backtick quoting. Emits LIMIT 18446744073709551615 when only OFFSET is requested (MySQL requires LIMIT before OFFSET). RETURNING is silently omitted.

• sqlite.rs — SQLite renderer. Uses ? placeholders and ANSI double-quote quoting. Supports RETURNING (SQLite 3.35+) and native FILTER (WHERE ...) on aggregates.

Array operators

PostgreSQL natively supports @> (contains), <@ (contained by), and && (overlaps) array operators via BinaryOp::ArrayContains, BinaryOp::ArrayContainedBy, and BinaryOp::ArrayOverlaps.

MySQL emulates contains / contained-by via JSON_CONTAINS(target, candidate). The generic MysqlDialect intentionally rejects overlap rendering because the workspace-wide "mysql" provider also covers MySQL-family backends where JSON_OVERLAPS is not guaranteed. SQLite uses json_each + correlated EXISTS predicates so JSON null elements are preserved instead of being lost to IN / NOT IN null semantics. Arrays are bound as JSON strings by the connector layer, so no special client-side handling is needed.