/**
 * A database executor that runs SQL and returns results.
 * All methods return Promises for a uniform async API.
 */
export interface Executor {
    /** Execute a query and return all matching rows. */
    all(sql: string, params: unknown[]): Promise<unknown[]>;
    /** Execute a query and return a single row or null. */
    get(sql: string, params: unknown[]): Promise<unknown>;
    /** Execute a statement (INSERT, UPDATE, DELETE, DDL) and return affected row count. */
    run(sql: string, params: unknown[]): Promise<{
        rowsAffected: number;
    }>;
    /** Run a callback inside a transaction. */
    transaction(fn: () => void | Promise<void>): Promise<void>;
    /** Close the underlying database connection. No-op if already closed. */
    close(): void;
}