AN ENHANCED NATURAL LANGUAGE PROCESSING MODEL FOR DATA EXTRACTION AND VISUALIZATION FROM SQL DATABASE STRUCTURES: A SYSTEMATIC REVIEW OF LITERATURE

This systematic review synthesizes the scholarly foundations underpinning an enhanced Natural Language Interface to Database system powered by Google's Gemini-2.5-Flash LLM. Spanning five core domains — Natural Language Processing fundamentals, Large Language Models, Text-to-SQL translation, database schema understanding, and automated data visualization — the review draws on 58 sources from peer-reviewed journals, conference proceedings, and technical reports (2017–2025). The review maps the trajectory from rule-based Natural Language Interface to Database prototypes to transformer-based deep learning systems, evaluates persistent challenges in schema linking and ambiguity resolution, and identifies critical research gaps in context-aware query generation and integrated visualization pipelines that motivate the present study.