Implementation:Eventual Inc Daft Session Set Catalog

Knowledge Sources	Daft Daft Docs
Domains	Data_Engineering, Catalog_Management
Last Updated	2026-02-08 00:00 GMT

Overview

Concrete tool for setting the active catalog and namespace context on a Daft Session provided by the Daft library.

Description

This implementation page documents both set_catalog and set_namespace methods on the Session class, as they together serve the single principle of catalog context setting. The set_catalog method sets the current catalog for the session (or unsets it with None), while set_namespace sets the current namespace for table resolution. Both methods delegate to the underlying Rust PySession. The set_catalog method raises a ValueError if the specified catalog does not exist.

Usage

Call sess.set_catalog("my_catalog") and sess.set_namespace("my_namespace") on a Session instance to configure the default scope for table name resolution.

Code Reference

Source Location

• Repository: Daft
• File: daft/session.py
• Lines: L575-594

Signature

def set_catalog(self, identifier: str | None) -> None

def set_namespace(self, identifier: Identifier | str | None) -> None

Import

from daft.session import Session

sess = Session()
sess.set_catalog("my_catalog")
sess.set_namespace("my_namespace")

I/O Contract

Inputs (set_catalog)

Name	Type	Required	Description
identifier	None	Yes	Catalog name to set as current, or None to unset the current catalog.

Inputs (set_namespace)

Name	Type	Required	Description
identifier	str | None	Yes	Namespace identifier to set as current, or None to unset the current namespace.

Outputs

Name	Type	Description
return	None	Both methods return None and modify session state in place.

Usage Examples

Basic Usage

from daft.session import Session

sess = Session()

# Attach and set a catalog
sess.attach_catalog(my_catalog, "analytics")
sess.set_catalog("analytics")

# Set the namespace
sess.set_namespace("production")

# Now unqualified table names resolve as analytics.production.<table_name>
tables = sess.list_tables()

# Unset the catalog
sess.set_catalog(None)

Related Pages

Implements Principle

• Principle:Eventual_Inc_Daft_Catalog_Context_Setting

Requires Environment

• Environment:Eventual_Inc_Daft_Python_PyArrow_Core