public static bool Exists <TKey, TEntity>(this IQueryStore <TKey, TEntity> queryStore, IStorageDbConnection conn, WhereClauseResult whereClause) where TKey : IEquatable <TKey> where TEntity : class, IEntity <TKey> { if (queryStore == null) { throw new ArgumentNullException(nameof(queryStore)); } return(queryStore.Exists(conn, whereClause, null)); }