With the prevalence of Large Language Models (LLMs), Text-to-SQL has made significant progress, yet applying it to massive, real-world databases remains a challenge. While previous works adopt a retrieve-then-generate framework, they struggle with the profound semantic gap between user queries and vague schema definitions. Existing methods relying on unidirectional query expansion often fail to bridge lexical mismatches, while graph-based approaches struggle to navigate schemas when explicit structural links (e.g., foreign keys) are missing. To address this, we propose Bi-SR, a retrieval framework that bridges this gap through a bidirectional semantic enhancement strategy. We simultaneously enrich vague table schemas offline and perform online generative query expansion—specifically predicting potential schema structures—to align user intent. Crucially, we introduce a dual-augmented contrastive training objective for the dense retriever, which trains the dense retriever to recognize the semantic correspondence between the LLM-expanded query intent and the detailed schema descriptions. Experiments on massive schema routing benchmarks constructed from BIRD and Spider demonstrate that Bi-SR achieves state-of-the-art performance and significantly empowers smaller models for cost-effective deployment.

As machine learning (ML) application continues to expand across diverse fields, there is a rising demand for ML code generation. In this paper, we aim at a critical research question: Can machines autonomously generate ML code for sophisticated, human-designed algorithms or solutions? To answer this question, we introduce a novel benchmark, MLAlgo-Bench, which includes two challenging tasks: 1) Generating code for ML algorithms including both traditional ML and modern deep learning-based methods, and 2) Giving humans solution sketches, writing ML code for solving practical tasks in Kaggle competitions. This benchmark is unique in its focus on the challenges of interpreting intricate human instructions and producing multi-step, high-complexity code, offering a rigorous test for current Large Language Model (LLM) capabilities. We introduce an automatic evaluation framework with comprehensive metrics such as task pass rate, relative performance metric, and time overhead. Currently, the top-performing models (Claude3.5-Sonet) achieve a 48.8% task completion rate on realizing machine learning algorithms, and a 21.6% rate for completing Kaggle competitions. Further analysis suggests substantial room for improvement.