import * as pg from 'pg';
import { PostgresDatabase } from './PostgresDatabase.js';
import { Database } from '../../Database.js';
import { DatabaseTransaction } from '../../DatabaseTransaction.js';
/**
 * A type alias representing a Postgres transaction. It extends the `PostgresTransactionImpl`
 * interface and includes the `PoolClient` interface.
 */
export type PostgresTransaction = PostgresTransactionImpl & pg.PoolClient;
/**
 * Represents a transaction in a Postgres database.
 */
export declare class PostgresTransactionImpl extends DatabaseTransaction {
    /**
     * A Pool object used for writing operations.
     * @readonly
     */
    readonly writer: pg.Pool;
    /**
     * A readonly property representing a pool reader.
     */
    readonly reader: pg.Pool;
    /**
     * Represents a database transaction using a PoolClient.
     * @type {PoolClient}
     */
    protected transaction: pg.PoolClient;
    /**
     * A protected property representing a database of type Database<PostgresTransaction>.
     * This property is used to interact with a Postgres database using transactions.
     */
    protected database: Database<PostgresTransaction>;
    /**
     * Constructs a new instance of the class with the provided writer, database, and optional reader.
     * @param {Pool} writer - The writer pool for database operations.
     * @param {PostgresDatabase} database - The Postgres database instance.
     * @param {Pool} [reader] - The reader pool for database operations (optional).
     */
    private constructor();
    /**
     * Creates a new database transaction using the provided writer and database instances.
     * @param {Pool} writer - The writer instance for the transaction.
     * @param {PostgresDatabase} database - The database instance for the transaction.
     * @param {Pool} [reader] - Optional reader instance for the transaction.
     * @returns {Promise<PostgresTransaction>} A promise that resolves to a new PostgresTransaction instance.
     */
    static newTransaction(writer: pg.Pool, database: PostgresDatabase, reader?: pg.Pool): Promise<PostgresTransaction>;
    /**
     * Initiates a transaction by connecting to the writer and executing a 'BEGIN' query.
     * @returns {Promise<void>} A promise that resolves when the transaction is successfully initiated.
     */
    protected doBegin: () => Promise<pg.QueryResult<any>>;
    /**
     * Executes a COMMIT query to commit the current transaction.
     * @returns A Promise that resolves when the COMMIT query is successfully executed.
     */
    protected doCommit: () => Promise<pg.QueryResult<any>>;
    /**
     * Rolls back the current transaction by executing a 'ROLLBACK' query.
     * @returns A Promise that resolves when the rollback is successful.
     */
    protected doRollback: () => Promise<pg.QueryResult<any>>;
}