//! Database connection, transaction management, and the `Executor` trait.
//!
//! Supports both PostgreSQL and SQLite backends via feature flags.
//! Both can be enabled simultaneously; the backend is selected at
//! runtime based on the `DATABASE_URL` scheme.
//!
//! ## Module layout
//!
//! - [`pool`] — `Db` connection pool wrapper
//! - [`tx`] — `Tx` transaction wrapper
//! - [`executor`] — `Executor` trait + `impl` for `Db` and `Tx`
//! - [`row_bound`] — `FlozRowBound` cfg-gated trait alias
//! - [`placeholder`] — `$N` → `?N` placeholder conversion
pub use Db;
pub use Tx;
pub use Executor;
pub use FlozRowBound;