DataUnitRegistry

class lsst.daf.butler.DataUnitRegistry

Bases: object

Instances of this class keep track of DataUnit relations.

Entries in this dict-like object represent DataUnit instances, keyed on DataUnit names.

Methods Summary

fromConfig(config[, builder])	Alternative constructor.
getByLinkName(name)	Get a DataUnit for which name is part of the link.
getJoin(lhs, rhs)	Return the DataUnitJoin that relates the given DataUnit names.
getPrimaryKeyNames(dataUnitNames)	Get all primary-key column names for the given dataUnitNames.
getRegionHolder(*dataUnitNames)	Return the DataUnit or DataUnitJoin that holds region for the given combination of DataUnits.
items()
keys()
values()

Methods Documentation

classmethod fromConfig(config, builder=None)

Alternative constructor.

Build a DataUnitRegistry instance from a Config object and an (optional) SchemaBuilder.

Parameters:

config : SchemaConfig

Registry schema configuration containing “DataUnits”, “dataUnitRegions”, and “dataUnitJoins” entries.

builder : SchemaBuilder, optional

When given, create sqlalchemy.core.Table entries for every DataUnit table.

getByLinkName(name)

Get a DataUnit for which name is part of the link.

Parameters:

name : str

Link name.

Returns:

dataUnit : DataUnit

The corresponding DataUnit instance.

Raises:

KeyError

When the provided name does not correspond to a link for any of the DataUnit entries in the registry.

getJoin(lhs, rhs)

Return the DataUnitJoin that relates the given DataUnit names.

While DataUnitJoins are associated with a specific ordering or lhs and rhs, this method tries both.

Parameters:

lhs : str or sequence

DataUnit name or sequence of names for one side of the join.

rhs : str or sequence

DataUnit name or sequence of names for the other side of the join.

Returns:

join : DataUnitJoin

The DataUnitJoin that relates the given DataUnits, or None.

getPrimaryKeyNames(dataUnitNames)

Get all primary-key column names for the given dataUnitNames.

Parameters:

dataUnitNames : sequence

A sequence of DataUnit names.

Returns:

primaryKeyNames : set

All primary-key column names for the given dataUnitNames.

getRegionHolder(*dataUnitNames)

Return the DataUnit or DataUnitJoin that holds region for the given combination of DataUnits.

Returned object can be either DataUnitJoin or DataUnit. Use table and/or regionColumn properties of returned object to retrieve region data from database table.

Returns:

`DataUnitJoin` or `DataUnit` instance.

items()

keys()

values()