Schema-Aware Localisation (SAL) for Oracle NL2SQL

A recent publication on arXiv (2607.22572) presents Schema-Aware Localisation (SAL), a middleware solution designed for Oracle NL2SQL that mitigates hallucination and schema grounding issues prevalent in large language models. SAL constructs a dynamic schema map by querying Oracle's USER_TAB_COLUMNS catalog, identifies pertinent subsets of tables for each question, and incorporates accurate context into LLM prompts. The SQL generated is assessed by the Hallucination Index (Hidx), which verifies alias.column references against the current catalog and automatically corrects any invalid references. This method does not necessitate model retraining and specifically addresses ORA-00904 invalid-identifier errors frequently encountered in enterprise Oracle databases.