import type { Knex } from 'knex';
type Row = Record<string, unknown>;
interface RelationshipModel {
    [key: string]: unknown;
    modelName: string;
    id?: number | string;
    stripColumns<T extends Record<string, unknown>>(model: T, keepInternalState?: boolean | undefined): T;
}
type RelatedModelCtor<T extends RelationshipModel = RelationshipModel> = new (properties?: Row) => T;
/**
 * Lazy relation query wrapper backed by Knex.
 *
 * Relation instances are {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise | Promise-like}:
 * `await farmer.profile()` auto-executes the query. Chain `where()` before awaiting
 * to refine the query, or call `first()` / `get()` explicitly.
 */
declare abstract class Relation<TResult, TRelated extends RelationshipModel = RelationshipModel> implements PromiseLike<TResult> {
    protected readonly Related: RelatedModelCtor<TRelated>;
    protected readonly query: Knex.QueryBuilder<Row, Row[]> | null;
    constructor(Related: RelatedModelCtor<TRelated>, query: Knex.QueryBuilder<Row, Row[]> | null);
    /**
     * Appends a `where` constraint to the underlying Knex query.
     *
     * @param args - Knex `where` arguments (object or column/value pairs).
     * @returns This relation instance for chaining.
     */
    where(...args: unknown[]): this;
    /**
     * Executes the relation query and returns the first matching related model.
     *
     * @param columns - Columns to select (default `'*'`).
     * @returns Related model instance, or `null` when no row matches.
     */
    first(columns?: string | string[]): Promise<TRelated | null>;
    /**
     * Executes the relation query and returns all matching related models.
     *
     * @param columns - Columns to select (default `'*'`).
     * @returns Array of related model instances (empty when no rows match).
     */
    get(columns?: string | string[]): Promise<TRelated[]>;
    /**
     * Allows `await relation` without calling `first()` or `get()` explicitly.
     *
     * @param onFulfilled - Success callback.
     * @param onRejected - Error callback.
     */
    then<TResult1 = TResult, TResult2 = never>(onFulfilled?: ((value: TResult) => TResult1 | PromiseLike<TResult1>) | null, onRejected?: ((reason: unknown) => TResult2 | PromiseLike<TResult2>) | null): Promise<TResult1 | TResult2>;
    protected abstract resolve(): Promise<TResult>;
}
/**
 * One-to-one relation. Awaiting resolves to a single related model or `null`.
 *
 * @typeParam T - Related model instance type.
 */
declare class HasOneRelation<T extends RelationshipModel = RelationshipModel> extends Relation<T | null, T> {
    protected resolve(): Promise<T | null>;
}
/**
 * One-to-many relation. Awaiting resolves to an array of related models.
 *
 * @typeParam T - Related model instance type.
 */
declare class HasManyRelation<T extends RelationshipModel = RelationshipModel> extends Relation<T[], T> {
    protected resolve(): Promise<T[]>;
}
/**
 * Inverse belongs-to relation. Awaiting resolves to the parent model or `null`.
 *
 * @typeParam T - Related model instance type.
 */
declare class BelongsToRelation<T extends RelationshipModel = RelationshipModel> extends Relation<T | null, T> {
    protected resolve(): Promise<T | null>;
}
export { Relation, HasOneRelation, HasManyRelation, BelongsToRelation, type RelationshipModel, type RelatedModelCtor, type Row, };