1. A system for analytical processing of data in a distributed data storage system, the system comprising a processor and a memory storing instructions, the instructions comprising: a data extraction module configured to perform one or more elementary analytical operations while extracting data from one or more source databases in one or more data formats, the one or more source databases having one or more types of constraints and structures wherein the one or more elementary analytical operations facilitates condition checking; and a validation module configured to perform a repetitive data sorting operation in one or more stages wherein the repetitive data sorting operation identifies and categorizes the extracted data as a valid data and an invalid data, and stores the valid data and the invalid data in one or more corresponding databases; a processing engine configured to perform one or more data refinement operations while the data is being extracted wherein the processing engine performs one or more data refinement operations in parallel to the one or more elementary analytical operations performed by the data extraction module, the processing engine comprising: a mapping module configured to perform one or more types of mapping operations of the categorized data based on one or more mapping rules wherein the one or more types of mapping operations include data mapping from one table to another table, from two or more data paths and splitting of data into multiple output paths in a single step; and a transformation module configured to perform a secondary analytical transforming operation, based on one or more business rules, of the mapped categorized data to obtain a transformed categorized data, wherein the transformed categorized data is stored in a target area in the distributed data storage system.