import { QuerySelect } from './query-select.model';
import { DbHelperModel } from '../db-helper-model.model';
import { Observable } from 'rxjs/Observable';
import { DbQuery } from '../db-query.model';
/**
 * @public
 * @class QueryCount
 *
 * @description
 * For design reasons this class should not be used directly.
 * Prefer use {@link Count} function.
 *
 * @param T @extends DbHelperModel a model declared with table and column annotations
 *
 * @example
 * ```typescript
 * // count todos
 * Count(Select(Todo).where({isDone: false}})).exec().subscribe((cout: number) => {
 *      // do something with the result...
 * }, (err) => {
 *      // do something with the error...
 * });
 * ```
 *
 * @author  Olivier Margarit
 * @since   0.2
 */
export declare class QueryCount<T extends DbHelperModel> {
    private querySelect;
    /**
     * @public
     * @constructor create instance of QueryCount
     * @param querySelect the query to count the result
     */
    constructor(querySelect: QuerySelect<T>);
    /**
     * @public
     * @method build should be removed to be a part of the private API
     *
     * @return {DbQuery} of the query with the string part and
     *          clauses params.
     */
    build(): DbQuery;
    /**
     * @public
     * @method exec to execute the query and asynchronously retreive result.
     *
     * @return {Observable<number>} observable to subscribe and returning a count number as result
     */
    exec(): Observable<number>;
}
/**
 * @public
 * @function Count
 *
 * @description
 * function helper to count element that a query could return
 *
 * @param T @extends DbHelperModel a model declared with table and column annotations
 *
 * @example
 * ```typescript
 * // count todos
 * Count(Select(Todo).where({isDone: false}})).exec().subscribe(count: number) => {
 *      // do something with the result...
 * }, (err) => {
 *      // do something with the error...
 * });
 * ```
 *
 * @return {QueryCount<T>} instance
 *
 * @author  Olivier Margarit
 * @since   0.2
 */
export declare function Count<T extends DbHelperModel>(select: QuerySelect<T>): QueryCount<T>;