Version materialization

Version materialization returns an entity’s state at a given time. The time can be an interval, an instant, a before, or an after.

Get state at time

Create an AgnosticEntity instance with the entity URI and a configuration dictionary, then call get_state_at_time():

import json
from time_agnostic_library.agnostic_entity import AgnosticEntity

with open(CONFIG_PATH) as f:
    config = json.load(f)

entity = AgnosticEntity(res=RES_URI, config=config)
entity.get_state_at_time(time=(START, END), include_prov_metadata=True)

The time is a tuple (START, END). If one value is None, only the other is considered. Dates must be in ISO 8601 format (e.g., 2023-01-01, 2023-01-01T00:00:00+00:00).

The output is a tuple of three elements:

(
    {
        TIME_1: ENTITY_QUAD_SET_AT_TIME_1,
        TIME_2: ENTITY_QUAD_SET_AT_TIME_2
    },
    {
        SNAPSHOT_URI_AT_TIME_1: {
            'generatedAtTime': TIME_1,
            'invalidatedAtTime': INVALIDATION_TIME,
            'wasAttributedTo': ATTRIBUTION,
            'hasUpdateQuery': UPDATE_QUERY,
            'hadPrimarySource': PRIMARY_SOURCE,
            'description': DESCRIPTION
        }
    },
    {
        OTHER_SNAPSHOT_URI_1: {
            'generatedAtTime': GENERATION_TIME,
            'invalidatedAtTime': INVALIDATION_TIME,
            'wasAttributedTo': ATTRIBUTION,
            'hasUpdateQuery': UPDATE_QUERY,
            'hadPrimarySource': PRIMARY_SOURCE,
            'description': DESCRIPTION
        }
    }
)

1. A dictionary mapping timestamps to entity quad sets within the specified interval. Each quad set is a set[tuple[str, ...]] where each tuple contains N3-encoded RDF terms (e.g., ("<http://example.com/s>", "<http://example.com/p>", "\"value\""))
2. Snapshots metadata for the returned states if include_prov_metadata is True, empty dictionary if False
3. Other snapshots’ provenance metadata if include_prov_metadata is True, empty dictionary if False

When include_related_objects, include_merged_entities, or include_reverse_relations are enabled, the output tuple has the same structure but each element gains an extra nesting level keyed by entity URI, since the result can contain multiple entities:

(
    {
        RES_URI_1: {
            TIME_1: ENTITY_QUAD_SET_AT_TIME_1,
            TIME_2: ENTITY_QUAD_SET_AT_TIME_2
        },
        RES_URI_2: {
            TIME_1: ENTITY_QUAD_SET_AT_TIME_1
        }
    },
    {
        RES_URI_1: {
            SNAPSHOT_URI: { ... }
        }
    },
    {
        RES_URI_1: {
            OTHER_SNAPSHOT_URI: { ... }
        }
    }
)

Get full history

To retrieve the complete history of an entity, use get_history():

entity = AgnosticEntity(res=RES_URI, config=config)
entity.get_history(include_prov_metadata=True)

The output is a two-element tuple:

(
    {
        RES_URI: {
            TIME_1: ENTITY_QUAD_SET_AT_TIME_1,
            TIME_2: ENTITY_QUAD_SET_AT_TIME_2
        }
    },
    {
        RES_URI: {
            SNAPSHOT_URI_AT_TIME_1: {
                'generatedAtTime': GENERATION_TIME,
                'invalidatedAtTime': INVALIDATION_TIME,
                'wasAttributedTo': ATTRIBUTION,
                'hadPrimarySource': PRIMARY_SOURCE,
                'description': DESCRIPTION,
                'hasUpdateQuery': UPDATE_QUERY,
                'wasDerivedFrom': [DERIVED_SNAPSHOT_URI_1, ...]
            }
        }
    }
)

1. A dictionary containing all versions of the entity, keyed by entity URI. Each version is a set[tuple[str, ...]] of N3-encoded quad tuples
2. All provenance metadata linked to that entity if include_prov_metadata is True, None if False

Get delta between versions

To compute the net difference between two versions of an entity without materializing either state, use get_delta():

entity = AgnosticEntity(res=RES_URI, config=config)
additions, deletions = entity.get_delta(
    time_start="2023-01-01T00:00:00+00:00",
    time_end="2023-06-01T00:00:00+00:00"
)

The method composes the stored SPARQL UPDATE queries in the interval into a net delta. The output is a tuple of two sets:

• additions (set[tuple[str, ...]]): quads present at time_end but not at time_start
• deletions (set[tuple[str, ...]]): quads present at time_start but not at time_end

If the entity was created within the range (no snapshot exists at or before time_start), all quads at time_end are returned as additions. If no changes occurred in the interval, both sets are empty.

Related entities

The history of an entity and all related entities can be obtained by setting the include_* parameters:

entity = AgnosticEntity(
    res=RES_URI,
    config=config,
    include_related_objects=True,
    include_merged_entities=True,
    include_reverse_relations=False
)
entity.get_history(include_prov_metadata=True)