The Death of Schema Linking? Text-to-SQL in the Age of Well-Reasoned Language Models

TL;DR

This paper investigates the necessity of schema linking in Text-to-SQL tasks with large language models, demonstrating that newer models can bypass traditional schema linking and still achieve high accuracy by using alternative techniques.

Contribution

It shows that schema linking can be omitted when using large language models within their context window, and introduces augmentation, selection, and correction techniques to improve performance.

Findings

New models effectively utilize relevant schema without explicit linking.

Omitting schema linking reduces errors caused by filtering irrelevant schema.

Achieved top accuracy of 71.83% on the BIRD benchmark.

Abstract

Schema linking is a crucial step in Text-to-SQL pipelines. Its goal is to retrieve the relevant tables and columns of a target database for a user's query while disregarding irrelevant ones. However, imperfect schema linking can often exclude required columns needed for accurate query generation. In this work, we revisit schema linking when using the latest generation of large language models (LLMs). We find empirically that newer models are adept at utilizing relevant schema elements during generation even in the presence of large numbers of irrelevant ones. As such, our Text-to-SQL pipeline entirely forgoes schema linking in cases where the schema fits within the model's context window in order to minimize issues due to filtering required schema elements. Furthermore, instead of filtering contextual information, we highlight techniques such as augmentation, selection, and correction, and adopt them to improve the accuracy of our Text-to-SQL pipeline. Our approach ranks first on the BIRD benchmark achieving an accuracy of 71.83%.