NoSQL: a análise da modelagem e consistência dos dados na era do Big Data

Abstract

The new storage models, known as NoSQL, arise to solve current data issues, defined by the properties volume, velocity and variety (3 V’s) established in the Big Data concept. These new storage models develop with the support of distributed computing and horizontal scalability, which allows the processing of the big amount of data necessary to the Big Data 3 V’s. In this thesis was used as theoretical framework the relational model, introducing its solutions and troubles. The relational model allowed the use of structures in secondary memory in a persistent way. Its modeling establishes rules to the creation of a solid data model, using mathematics concepts and tangible representation to the human interpretation. The properties defined by the transactional model ACID, implemented in the relational SGBDs brings assurance consistency of the storaged data. The use of the relational model distanced the transient structures in primary memory, used in execution time by software applications and those persisted in secondary memory, an effect known as impedance mismatch. The new models presented by the categories of the NoSQL, bring transient structures previously used in primary memory. The use of distributed computing presents the possibility of the transaction and storage of the data for several computers, known as nodes, present in clusters. Distributed computing increases availability and decreases the likelihood of system failures. However, its use brings inconsistency to the data, according to the properties defined by the CAP Theorem (FOX; BREWER, 1999). This study was carried out on behalf of a bibliographic review, analyzing primarily the needs, which led to the relational model creation. Later, we establish the state of the theoretical and techniques art that involves the NoSQL and the distributed data processing system, just as the different categories introduced by it. An adequate tool were chosen and analyzed from each NoSQL category, for the proper understanding about your structure, metadata and operations. Aside from establish the state of art regarding NoSQL, we demonstrate how the transient and persistent data structures rapprochement becomes possible due to the current machine advances, such as the possibilities to the consistency effect processing, outlined by CAP Theorem