ForeignKeySpec

class lsst.daf.butler.ForeignKeySpec(table: str, source: Tuple[str, ...], target: Tuple[str, ...], onDelete: Optional[str] = None)

Bases: object

A struct-like class used to define a foreign key constraint in a logical Registry table.

Attributes Summary

onDelete

SQL clause indicating how to handle deletes to the target table.

Methods Summary

fromConfig(config, *args, **kwds)
toSqlAlchemy(tableName, schema)	Construct a SQLAlchemy ForeignKeyConstraint corresponding to this specification.

Attributes Documentation

onDelete = None

SQL clause indicating how to handle deletes to the target table.

If not None, should be either “SET NULL” or “CASCADE”.

Methods Documentation

classmethod fromConfig(config, *args, **kwds)

toSqlAlchemy(tableName: str, schema: lsst.daf.butler.core.schema.Schema) → sqlalchemy.sql.schema.ForeignKeyConstraint

Construct a SQLAlchemy ForeignKeyConstraint corresponding to this specification.

Parameters:

tableName : str

Name of the logical table to which this constraint belongs (the table for source columns).

schema : Schema

Object represening the full schema. May be modified in-place.

Returns:

constraint : sqlalchemy.ForeignKeyConstraint

SQLAlchemy version of the foreign key constraint.