From Textual Columns to Query Plans: A Unified Relational-Semantic Execution Framework for Hybrid Query Processing

Nima Shahbazi, Seiji Maekawa, Nikita Bhutani, Estevam Hruschka


Abstract
Existing table question answering systems face a key trade-off: approaches designed for relational databases scale efficiently but assume fully structured schemas, while LLM-based methods support flexible reasoning over unstructured text but struggle to scale to large and multi-table datasets. This limits their applicability to semi-structured data, where answering a query may require dynamically recovering latent schema elements from free-form text before symbolic execution can proceed. We present OmniTQA, an operator-centric framework that unifies relational execution and LLM-based semantic reasoning within a single query runtime. OmniTQA compiles queries into directed acyclic graphs (DAGs) of relational and semantic operators, enabling cost-aware optimization, dual-engine execution, and parallel exploration of alternative semantic groundings under ambiguity. Experiments on structured and semi-structured benchmarks show that OmniTQA substantially outperforms existing approaches on hybrid data settings while remaining competitive on structured datasets.
Anthology ID:
2026.findings-aacl.200
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3979–4002
Language:
URL:
https://aclanthology.org/2026.findings-aacl.200/
DOI:
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Cite (ACL):
Nima Shahbazi, Seiji Maekawa, Nikita Bhutani, and Estevam Hruschka. 2026. From Textual Columns to Query Plans: A Unified Relational-Semantic Execution Framework for Hybrid Query Processing. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 3979–4002, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
From Textual Columns to Query Plans: A Unified Relational-Semantic Execution Framework for Hybrid Query Processing (Shahbazi et al., Findings 2026)
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https://aclanthology.org/2026.findings-aacl.200.pdf