Definitions in PASTA-ELN

Definition overview

In scientific contexts, properties are often defined with specific details. For instance, a temperature measurement might be represented as:

temperature_A : 97

Here, temperature_A is referred to as the key, while 97 represents the value, which in this example is a numerical figure. However, this representation lacks essential information, such as:

  • Scientific unit: Units may vary across measurements.

  • Description: Could include text in the user's language, an official explanation, or other clarifying details.

  • IRI/URL: A reference to an authoritative online resource, such as an ontology node or standardized definition.

To address these gaps, the entry could be restructured as follows:

temperature_A : {
    'value': 97,
    'unit': 'C',
    'description': 'Temperature inside the instrument’s right side',
    'IRI': 'https://www.wikidata.org/wiki/Q11466'}

Additional metadata can further enrich each property, such as:

  • Uncertainty: To account for the margin of error in values.

  • Data type: For example, integer, text, date, etc.

  • Allowable values: For instance, temperatures cannot be less than 0 K.

While including this information enhances the metadata's richness, it also increases complexity for both users and developers. PASTA-ELN seeks to strike a balance between usability—minimizing bugs by keeping things straightforward—and offering users the flexibility to include necessary details. Most additional metadata can be incorporated within the value or description fields.

Handling Multiple Datasets and Data Types

When a specific definition is used across multiple database locations, duplicating the associated information is inefficient. To optimize this, PASTA-ELN stores the description and IRI for each key in a centralized table (referred to as definitions). However, the value and unit can either be stored independently or inherit from the master definition. In cases where both individual and master definitions specify a unit, precedence is logically given to the individual value's unit.

This approach ensures that each key is unique and appears only once. For example:

  • If "height" is defined for instruments, the same "height" key applies to samples, sharing the same description and IRI but potentially differing in units.

  • If distinct descriptions are required, unique keys must be assigned to differentiate them.