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 analytical operations to extract 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; and a processing module configured to perform one or more data refinement operations to categorize the data while the data is being extracted, the processing module 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; and a transformation module configured to perform an 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.