liveBook · Manning

Parquet_schema

As explained in DuckDB in Action

parquet_schema is a DuckDB table function that returns the schema metadata stored inside a Parquet file.

parquet_schema is a DuckDB table function for inspecting the schema metadata stored inside a Parquet file. It reveals column names, physical types, and logical interpretations before you query or optimize the data. section 5.5 section 10.4.3

Use it to:

  • Compare on-disk types with converted_type and logical_type values. section 5.5

Inspect the useful columns

FROM parquet_schema('atp/atp_rankings.parquet') SELECT name, type, converted_type, logical_type;

How DuckDB in Action covers it

How deep it goes
Exposes metadata fields and physical-versus-logical types, but leaves value-range checks and type optimization to separate queries.
Examples
Uses ATP rankings and NYC taxi Parquet files to display column names and stored types.
What it assumes
Assumes familiarity with DuckDB SQL and querying Parquet files.
What you can do after
Evaluate Parquet columns by querying their names, physical types, and logical interpretations.
How it connects
Connects Parquet physical types with logical types, read_parquet, and parquet_metadata.
Cover of DuckDB in Action
liveBookmanning.com
Read DuckDB in Action on liveBook Get the book at manning.com

Related concepts

This explainer was generated by Manning's knowledge graph from the text of DuckDB in Action. The section links point to the parts of the book it draws on.