Experiment data and analysis result classes

docs/apidocs/database_service.rst

@@ -0,0 +1,6 @@
+.. _qiskit-experiments:
+
+.. automodule:: qiskit_experiments.database_service
+   :no-members:
+   :no-inherited-members:
+   :no-special-members:

docs/apidocs/index.rst

@@ -14,4 +14,5 @@ Qiskit Experiments API Reference
     tomography
     analysis
     data_processing
+    database_service
 

qiskit_experiments/database_service/__init__.py

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+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2021.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""
+=============================================================
+Database Service (:mod:`qiskit_experiments.database_service`)
+=============================================================
+
+.. currentmodule:: qiskit_experiments.database_service
+
+This subpackage contains classes used to define the data structure of
+an experiment, including its data, metadata, analysis results, and figures, as
+well as the interface to an experiment database service. An experiment database
+service allows one to store, retrieve, and query experiment related data.
+
+:class:`DbExperimentDataV1` is the main class that defines the structure of
+experiment data, which consists of the following::
+
+    * Results from circuit execution, which is called ``data`` in this class.
+      The :meth:`DbExperimentDataV1.add_data`
+      method allows you to add circuit jobs and job results. If jobs are added,
+      the method asynchronously waits for them to finish and extracts job results.
+      :meth:`DbExperimentDataV1.data` can then be used to retrieve this data.
+      Note that this data is not saved in the database. It is included in this
+      class only for convenience.
+
+    * Experiment metadata. This is a freeform keyword-value dictionary. You can
+      use this to save extra information, such as the physical qubits the experiment
+      operated on, in the database. :meth:`DbExperimentDataV1.set_metadata` and
+      :meth:`DbExperimentDataV1.metadata` are methods to set and retrieve metadata,
+      respectively.
+
+    * Analysis results. It is likely that some analysis is to be done on the
+      experiment data once the circuit jobs finish, and the result of this
+      analysis can be stored in the database. Similar to ``DbExperimentDataV1``,
+      :class:`DbAnalysisResultV1` defines the data structure of an analysis
+      result and provides methods to interface with the database. Being a separate
+      class, :class:`DbAnalysisResultV1` allows you to modify an analysis result
+      without modifying the experiment data.
+
+    * Figures. Some analysis functions also generate figures, which can also be
+      saved in the database.
+
+:class:`DatabaseServiceV1` provides low-level abstract interface for accessing the
+database, such as :meth:`DatabaseServiceV1.create_experiment` for creating a
+new experiment entry and :meth:`DatabaseServiceV1.update_experiment` for
+updating an existing entry. :class:`DbExperimentDataV1` has methods that wrap
+around some of these low-level database methods. For example,
+:meth:`DbExperimentDataV1.save` calls :meth:`DatabaseServiceV1.create_experiment`
+under the cover to save experiment related data. The low-level methods are only
+expected to be used when you want to interact with the database directly - for
+example, to retrieve a saved analysis result.
+
+Currently only IBM Quantum provides this database service, but we plan on having
+a local database service in the near future.
+
+Classes
+=======
+
+.. autosummary::
+   :toctree: ../stubs/
+
+   DbExperimentData
+   DbExperimentDataV1
+   DbAnalysisResult
+   DbAnalysisResultV1
+   DatabaseService
+   DatabaseServiceV1
+
+
+Exceptions
+==========
+
+.. autosummary::
+   :toctree: ../stubs/
+
+   DbExperimentDataError
+   DbExperimentEntryExists
+   DbExperimentEntryNotFound
+"""
+
+from .db_experiment_data import DbExperimentData, DbExperimentDataV1
+from .db_analysis_result import DbAnalysisResult, DbAnalysisResultV1
+from .database_service import DatabaseService, DatabaseServiceV1
+from .exceptions import DbExperimentDataError, DbExperimentEntryExists, DbExperimentEntryNotFound