OpaqueTableStorageManager

class lsst.daf.butler.registry.interfaces.OpaqueTableStorageManager

Bases: abc.ABC

An interface that manages the opaque tables in a Registry.

OpaqueTableStorageManager primarily serves as a container and factory for OpaqueTableStorage instances, which each provide access to the records for a different (logical) opaque table.

Notes

Opaque tables are primarily used by Datastore instances to manage their internal data in the same database that hold the Registry, but are not limited to this.

While an opaque table in a multi-layer Registry may in fact be the union of multiple tables in different layers, we expect this to be rare, as Registry layers will typically correspond to different leaf Datastore instances (each with their own opaque table) in a ChainedDatastore.

Methods Summary

get(name)	Return an object that provides access to the records associated with an opaque logical table.
initialize(db, context)	Construct an instance of the manager.
register(name, spec)	Ensure that this layer can hold records for the given opaque logical table, creating new tables as necessary.

Methods Documentation

get(name: str) → Optional[lsst.daf.butler.registry.interfaces._opaque.OpaqueTableStorage]

Return an object that provides access to the records associated with an opaque logical table.

Parameters:

name : str

Name of the logical table.

Returns:

records : OpaqueTableStorage or None

The object representing the records for the given table in this layer, or None if there are no records for that table in this layer.

Notes

Opaque tables must be registered with the layer (see register) by the same client before they can safely be retrieved with get. Unlike most other manager classes, the set of opaque tables cannot be obtained from an existing data repository.

classmethod initialize(db: lsst.daf.butler.registry.interfaces._database.Database, context: lsst.daf.butler.registry.interfaces._database.StaticTablesContext) → lsst.daf.butler.registry.interfaces._opaque.OpaqueTableStorageManager

Construct an instance of the manager.

Parameters:

db : Database

Interface to the underlying database engine and namespace.

context : StaticTablesContext

Context object obtained from Database.declareStaticTables; used to declare any tables that should always be present in a layer implemented with this manager.

Returns:

manager : OpaqueTableStorageManager

An instance of a concrete OpaqueTableStorageManager subclass.

register(name: str, spec: lsst.daf.butler.core.ddl.TableSpec) → lsst.daf.butler.registry.interfaces._opaque.OpaqueTableStorage

Ensure that this layer can hold records for the given opaque logical table, creating new tables as necessary.

Parameters:

name : str

Name of the logical table.

spec : TableSpec

Schema specification for the table to be created.

Returns:

records : OpaqueTableStorage

The object representing the records for the given element in this layer.

Notes

This operation may not be invoked within a transaction context block.