/** Describes the result of a query from a {@link PGProvider} */
export interface PGProviderResult {
    /** The SQL command that generated this result (`SELECT`, `INSERT`, ...) */
    command: string;
    /** Number of rows affected by this query (e.g. added rows in `INSERT`) */
    rowCount: number;
    /** Fields description with `name` (column name) and `oid` (type) */
    fields: [name: string, oid: number][];
    /** Result rows, as an array of unparsed `string` results from `libpq` */
    rows: (string | null)[][];
}
export interface PGProviderConnection {
    query(text: string, params?: (string | null)[]): Promise<PGProviderResult>;
}
export interface PGProviderConstructor<Connection extends PGProviderConnection = PGProviderConnection> {
    new (url: URL): PGProvider<Connection>;
}
export interface PGProvider<Connection extends PGProviderConnection = PGProviderConnection> extends PGProviderConnection {
    /** The URL used to create this provider, devoid of any credentials */
    readonly url: Readonly<URL>;
    acquire(): Promise<Connection>;
    release(connection: Connection): Promise<void>;
    destroy(): Promise<void>;
}
export declare abstract class AbstractPGProvider<Connection extends PGProviderConnection = PGProviderConnection> implements PGProvider<Connection> {
    constructor(url: URL | string);
    get url(): Readonly<URL>;
    abstract acquire(): Promise<Connection>;
    abstract release(connection: PGProviderConnection): Promise<void>;
    query(text: string, params?: (string | null)[]): Promise<PGProviderResult>;
    destroy(): Promise<void>;
}
/** Register a provider, associating it with the specified protocol */
export declare function registerProvider(protocol: string, constructor: PGProviderConstructor): void;
/** Create a new {@link PGProvider} instance for the specified URL */
export declare function createProvider(url: URL): PGProvider;