import DataLoader from "dataloader";
import { Knex } from "knex";
import { Knex as KnexOriginal } from "knex";
import { KeyValueCache } from "@apollo/utils.keyvaluecache";
declare module "knex" {
    namespace Knex {
        type KnexConfig = {
            client: string;
            connection: string | undefined;
        };
        type BatchCallback = (query: Knex.QueryBuilder, keys: readonly any[]) => Promise<any[]>;
        interface QueryBuilder {
            cache<TRecord extends {}, TResult>(value: number): KnexOriginal.QueryBuilder<TRecord, TResult>;
            batch(callback: BatchCallback): BatchedLoader;
        }
    }
}
export interface DataSourceKnex extends Knex {
    cache?: Knex.QueryBuilder["cache"];
    batch?: Knex.QueryBuilder["batch"];
}
export interface BatchedLoader<T = unknown, K = any> extends DataLoader<T, K> {
}
export declare type BatchedSQLDataSourceProps<Context = any> = {
    knexConfig: Knex.KnexConfig | DataSourceKnex;
    writeKnexConfig?: Knex.KnexConfig | DataSourceKnex;
    cache?: KeyValueCache;
    context?: Context;
};
export declare class BatchedSQLDataSource {
    cache: BatchedSQLDataSourceProps["cache"];
    context: BatchedSQLDataSourceProps["context"];
    db: {
        query: DataSourceKnex;
        write: DataSourceKnex;
    };
    constructor(config: BatchedSQLDataSourceProps);
    private _extendKnex;
    private _connectToDatabase;
    private _batchQuery;
    private _cacheQuery;
}