Concepts

Delta Funnel has a small workflow model. These terms appear across the Rust and Python APIs.

Session

A session owns registered sources, derived SQL tables, default options, and the default SQL Server connection. In Python, create one with Session(...).

Source

A source is an input table, such as a Delta Lake table loaded from a local path or object-store URI. A named source is registered in the SQL catalog and can be referenced by queries.

Table

A table is a lazy query object. It may represent a Delta source or SQL derived from other registered tables. Creating a table does not by itself execute rows.

Output

An output describes where a table should be written in SQL Server. Use Table.to_mssql(...) to create an output spec for Session.write_all(...), or use Table.write_to_mssql(...) for a single output.

Report

A report describes what Delta Funnel planned or executed. Dry-run reports describe the plan without writing rows. Execute reports describe the write workflow and validation facts.

Reports are structured data, not log text. Sensitive values such as connection strings and credentials should not appear in them.