import { OnModuleDestroy, OnModuleInit } from '@nestjs/common';
/** RunResult compatible with better-sqlite3 for callers that use .changes / .lastInsertRowid */
export interface RunResult {
    changes: number;
    lastInsertRowid: number;
}
export declare class DatabaseService implements OnModuleInit, OnModuleDestroy {
    private sqlDb;
    private dbPath;
    private initPromise;
    onModuleInit(): Promise<void>;
    private doInit;
    private getDb;
    private runMigrations;
    run(sql: string, params?: unknown[]): RunResult;
    /**
     * 使用文件 DB 时立即落盘。每次 run() 写入后都会调用，保证「每次保存马上写到磁盘」。
     * 落盘失败时重新抛出，便于上层返回错误、前端不乐观更新，避免「删了但重启又出现」。
     */
    private persistIfFile;
    /** 供删除等关键操作后显式落盘，确保删除结果持久化 */
    persist(): void;
    get<T>(sql: string, params?: unknown[]): T | undefined;
    all<T>(sql: string, params?: unknown[]): T[];
    onModuleDestroy(): void;
}