Primary keys and foreign keys are rarely used in data science workloads. In our performance guide, we recommend users to avoid using primary keys unless they are absolutely necessary [1]. In workloads running in infrastructure components, keys and constraints are more important, and they are supported by DuckDB (but currently some of them can only be added when the table is created).

[1] https://duckdb.org/docs/guides/performance/schema#microbench...