1. Digital SNOWTAM Trial: AIXM Database Design
Pulsar Consulting sa
Avenue Pasteur, 17
1300 Wavre
Belgium
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2. Agenda
General Guidelines
Temporality Model Implementation
Common Properties and Geoms
Notes Implementation
ICAO SNOWTAMs Implementation (not included in AIXM)
Null Properties Implementation (xNOTAM-Trial)

3. Implemented only a subset of AIXM 5.x Manual design (no generation)
General Guidelines
Implemented only a subset of AIXM 5.x
Manual design (no generation)
As close as possible to the AIXM Conceptual Model
One table per class for <<feature>> and <<object>>
Inheritance generally not applied at the database level
Inherited fields repeated in each table
avoid too many joins
Notes and many to many relationships
Enumerations  database constraint (!! AIXM 5.1 !!)

4. Temporality Model Implementation
Timeslice types:
BASELINE
PERMDELTA
TEMPDELTA
STATE (~ long SNAPSHOT)
(interpretation)
Fields about temporality are repeated in all timeslice tables to avoid having to many joins (validTime, interpretation, sequenceNumber, etc…)
Valid Time / Feature Lifetime
Sequence Number / Correction Number as explained in the temporality model (in xSNOWTAM, only one TempDelta can be valid at the specific time)

5. Common Properties and Geoms
* Added technical fields in all tables
Tracing information
Pre-calculated information and aggregated geoms
Runway thirds geoms

6. Notes Implementation
One Note table linked to all timeslices tables (many to many)
No constraint on property_name (but managed by applications)

7. ICAO SNOWTAMs Implementation (not included in AIXM)
The timeslices impacted by a SNOWTAM are linked to the associated SNOWTAM. Furthermore, the ICAO SNOWTAM is linked to its associated AirportHeliport Feature:

8. NULL Properties Implementation
Timeslices may explicitly set a property to ‘NULL’: means this property has no value anymore (the property is changed to ‘NULL’).
In Digital NOTAM Trial: new “is null” boolean property for each nullable simple or complex property = concatenation of the property name and the suffix “_N” (was generated from the db schema)
Not needed in Digital SNOWTAM. Contaminations last no more than 24 hours and a “green” SNOWTAM is emitted for ‘all clear’ situation

9. QUESTIONS