Text-to-SQL with LLM APIs: Architecture, Safety, Evaluation, and Cost

Text-to-SQL lets users ask data questions in plain English. LLM APIs make this easier, but generated SQL needs guardrails.

Architecture

A basic flow:

1. User asks a question. 2. System retrieves relevant schema. 3. Model drafts SQL. 4. Validator checks the query. 5. Query runs with user permissions. 6. Model explains the result.

Safety controls

Use read-only credentials, row-level permissions, query limits, blocked statements, and execution timeouts.

Evaluation

Test with real business questions. Track query correctness, execution errors, latency, and user satisfaction.

Final thoughts

Text-to-SQL is powerful when paired with schema retrieval, validation, permissions, and careful evaluation.