openclean.data.archive.base module

Interfaces and base classes for the data store that is used to maintain all versions of a data frame.

class openclean.data.archive.base.ActionHandle

Bases: object

Interface for action handles. Defines the serializatio method to_dict that is used to get a descriptor for the action that created a dataset snapshot.

abstract to_dict() → Dict

Get a dictionary serialization for the action.

Return type

dict

class openclean.data.archive.base.ArchiveStore

Bases: object

Interface for the data store that is used to maintain the different versions of a dataset that a user creates using the openclean (Jupyter) API.

abstract apply(operators: Union[histore.document.operator.DatasetOperator, List[histore.document.operator.DatasetOperator]], origin: Optional[int] = None, validate: Optional[bool] = None) → List[histore.archive.snapshot.Snapshot]

Apply a given operator or a sequence of operators on a snapshot in the archive.

The resulting snapshot(s) will directly be merged into the archive. This method allows to update data in an archive directly without the need to checkout the snapshot first and then commit the modified version(s).

Returns list of handles for the created snapshots.

Note that there are some limitations for this method. Most importantly, the order of rows cannot be modified and neither can it insert new rows at this point. Columns can be added, moved, renamed, and deleted.

Parameters

  • operators (histore.document.operator.DatasetOperator or) – list of histore.document.stream.DatasetOperator Operator(s) that is/are used to update the rows in a dataset snapshot to create new snapshot(s) in this archive.

  • origin (int, default=None) – Unique version identifier for the original snapshot that is being updated. By default the last version is updated.

  • validate (bool, default=False) – Validate that the resulting archive is in proper order before committing the action.

Return type

histore.archive.snapshot.Snapshot

abstract checkout(version: Optional[int] = None) → pandas.core.frame.DataFrame

Get a specific version of the dataset. The dataset snapshot is identified by the unique version identifier.

Returns the data frame and version number for the dataset snapshot.

Raises a ValueError if the given version is unknown.

Parameters

version (int) – Unique dataset version identifier.

Return type

pd.DataFrame

Raises

ValueError –

abstract commit(source: Union[pandas.core.frame.DataFrame, str, histore.document.base.Document], action: Optional[openclean.data.archive.base.ActionHandle] = None, checkout: Optional[bool] = False) → Union[pandas.core.frame.DataFrame, str, histore.document.base.Document]

Insert a new dataset snapshot.

Returns the inserted data frame with potentially modified row indexes.

Parameters

  • source (openclean.data.stream.base.Datasource) – Input data frame or stream containing the new dataset version that is being stored.

  • action (openclean.data.archive.base.ActionHandle, default=None) – Optional handle of the action that created the new dataset version.

  • checkout (bool, default=False) – Checkout the commited snapshot and return the result. This option is required only if the row index of the given data frame has been modified by the commit operation, i.e., if the index of the given data frame contained non-integers, negative values, or duplicate values.

Return type

openclean.data.stream.base.Datasource

abstract last_version() → int

Get the version identifier for the last dataset snapshot.

Return type

int

Raises

ValueError –

abstract metadata(version: Optional[int] = None) → openclean.data.metadata.base.MetadataStore

Get metadata that is associated with the referenced dataset version. If no version is specified the metadata collection for the latest version is returned.

Raises a ValueError if the specified version is unknown.

Parameters

version (int) – Unique dataset version identifier.

Return type

openclean_.data.metadata.base.MetadataStore

Raises

ValueError –

abstract open(version: Optional[int] = None) → histore.archive.reader.SnapshotReader

Get a stream reader for a dataset snapshot.

Parameters

version (int, default=None) – Unique version identifier. By default the last version is used.

Return type

openclean.data.archive.base.SnapshotReader

abstract rollback(version: int) → pandas.core.frame.DataFrame

Rollback the archive history to the snapshot with the given version identifier.

Returns the data frame for the napshot that is now the last snapshot in the modified archive.

Parameters

version (int) – Unique identifier of the rollback version.

Return type

pd.DataFrame

abstract schema() → histore.archive.schema.ArchiveSchema

Get the schema history for the archived dataset.

Return type

openclean.data.archive.base.ArchiveSchema

abstract snapshots() → List[histore.archive.snapshot.Snapshot]

Get list of handles for all versions of the dataset.

Return type

list of histore.archive.snapshot.Snapshot

Raises

ValueError –

openclean.data.archive.base.create(dataset: str, source: Optional[Union[pandas.core.frame.DataFrame, str, histore.document.base.Document]], primary_key: Optional[List[str]], replace: Optional[bool] = False) → histore.archive.base.Archive

Create a new archive for a dataset with the given identifier. If an archive with the given identifier exists it will be replaced (if the replace flag is True) or an error is raised.

Parameters

  • dataset (string) – Unique dataset identifier.

  • source (openclean.data.archive.base.Datasource, default=None) – Initial dataset snapshot that is loaded into the created archive.

  • primary_key (list of string) – List of primary key attributes for merging snapshots into the created archive.

  • replace (bool, default=False) – Replace an existing archive with the same name if it exists.

Return type

histore.archive.base.Archive

Raises

ValueError –

openclean.data.archive.base.delete(dataset: str)

Delete the existing archive for a dataset. Raises a ValueError if the dataset is unknown.

Parameters

dataset (string) – Unique dataset identifier.

Raises

ValueError –

openclean.data.archive.base.get(dataset: str) → histore.archive.base.Archive

Get the existing archive for a dataset. Raises a ValueError if the dataset is unknown.

Parameters

dataset (string) – Unique dataset identifier.

Return type

histore.archive.base.Archive

Raises

ValueError –

openclean.data.archive.base.manager() → histore.archive.manager.persist.PersistentArchiveManager

Get instance of the archive manager that is used to maintain master datasets.

Return type

histore.archive.manager.base.ArchiveManager