Measurement

class specatalog.models.measurements.Measurement(**kwargs)[source]

Base class representing a single measurement.

This model defines the core metadata shared by all measurement types in the system (e.g., TREPR, CWEPR, PulseEPR). It serves as the root of a polymorphic SQLAlchemy hierarchy, with method acting as the discriminator. Subclasses inherit these fields and may define additional, technique-specific information.

The measurement belongs to exactly one Molecule instance, and contains essential experiment metadata.

Polymorphism

SQLAlchemy polymorphic behaviour is used to distinguish different measurement techniques:

polymorphic_on – the method column
polymorphic_identity – "base" for this class

Subclasses should set their own polymorphic_identity value.

Relationships

moleculeMolecule: The molecule to which the measurement belongs. Configured as a required foreign key with cascade delete behaviour.

id

Primary key identifying the measurement.

Type:: int

molecular_id

Foreign key referencing molecules.id. Required.

Type:: int

method

Polymorphic discriminator describing the measurement technique (e.g., "trepr", "cwepr", "pulse_epr").

Type:: str

temperature

Measurement temperature in Kelvin (or laboratory-specific units).

Type:: float

solvent

Solvent used in the experiment.

Type:: str

concentration

Concentration of the sample, if provided.

Type:: str or None

date

Date on which the measurement was performed.

Type:: datetime.date

measured_by

The operator who performed the measurement.

Type:: str

location

Laboratory or instrument location of the measurement.

Type:: str or None

device

Device/instrument identifier.

Type:: str or None

series

Optional series identifier grouping related measurements.

Type:: str or None

path

Absolute path to the associated measurement directory in the archive. Must be unique.

Type:: str

corrected

True if the measurement has been corrected.

Type:: bool

evaluated

True if the measurement has been analysed.

Type:: bool

Notes

The tablename is measurements
All measurement subclasses inherit timestamps from TimeStampedModel.
The path field is unique, ensuring that individual measurements are not duplicated.

Examples

Creating a measurement:

>>> from measurements import Measurement
>>> from molecules import Molecule
>>> mol = Molecule(...)
>>> m = Measurement(
...     molecule=mol,
...     method="TREPR",
...     temperature=295.0,
...     solvent="Toluene",
...     date=date(2025, 1, 4),
...     measured_by="Alice",
...     path="/data/M12/",
...     corrected=False,
...     evaluated=False,
... )
>>> session.add(m)
>>> session.commit()