Closes pathwaycom#224. This commit introduces dynamic schema exploration for pw.io.postgres.read, pw.io.mysql.read, and pw.io.mssql.read, allowing users to omit the schema parameter when initializing database readers. ### Approach Instead of adding heavy Python-level database drivers (e.g., SQLAlchemy) to query the schemas, this implementation extends the existing internal Rust connectors to extract metadata directly from INFORMATION_SCHEMA and sys. The results are mapped directly to Pathway Schema definitions via schema_builder. ### Key Changes - **Rust Backend**: Exposes postgres_explore_schema, mysql_explore_schema, and mssql_explore_schema via PyO3 in python_api.rs. These functions securely invoke standard metadata queries utilizing internal iberius, mysql, and okio-postgres connections. - **Python Connectors**: Updates __init__.py for Postgres, MySQL, and MSSQL to handle schema=None. When triggered, they fetch schema topology from the Rust backend and construct a dynamic pw.Schema mapping. - **Primary Key Handling**: Automatically explores and applies primary_key=True properties to the corresponding pw.column_definition elements. If no PK is found, the engine logs a visible warning to inform the user about potential CDC/streaming issues. - **User Visibility**: The dynamically inferred schema is logged at startup, allowing developers to easily copy it into their codebase if they require stricter type enforcement down the line. This zero-dependency approach ensures type safety parity while vastly improving the developer experience for database onboarding.

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Commits

Commits on Jul 3, 2026

feat(io): implement automated schema exploration for SQL connectors

chore(duckdb): allow clippy::struct_excessive_bools on DuckDbWriter

Commits on Jul 13, 2026

Merge branch 'main' of https://github.com/pathwaycom/pathway into feature/automated-schema-exploration

chore: fix flake8 warnings in test_common.py