TopologicalExtentDatabaseRepresentation

class lsst.daf.butler.TopologicalExtentDatabaseRepresentation

Bases: abc.ABC

An abstract base class whose subclasses provide a mapping from the in-memory representation of a TopologicalSpace region to a database-storage representation, and whose instances act like a SQLAlchemy-based column expression.

Methods Summary

fromSelectable(selectable)	Construct an instance that represents a logical column (which may actually be backed by multiple columns) in the given table or subquery.
overlaps(other)	Return a boolean SQLAlchemy column expression representing an overlap test between this logical column and another of the same type.

Methods Documentation

classmethod fromSelectable(selectable: sqlalchemy.sql.selectable.FromClause) → _S

Construct an instance that represents a logical column (which may actually be backed by multiple columns) in the given table or subquery.

Parameters:

selectable : sqlalchemy.sql.FromClause

SQLAlchemy object representing a table or subquery.

Returns:

representation : TopologicalExtentDatabaseRepresentation

Object representing a logical column.

overlaps(other: _S) → sqlalchemy.sql.elements.ColumnElement

Return a boolean SQLAlchemy column expression representing an overlap test between this logical column and another of the same type.

Parameters:

other : type(self)

Another instance of the exact same type as self.

Returns:

expression : sqlalchemy.sql.ColumnElement

A boolean SQLAlchemy expression.