An effectivity satellite.
- class diepvries.effectivity_satellite.EffectivitySatellite(schema, name, fields, driving_keys, *args, **kwargs)¶
An effectivity satellite is a special type of satellite with the purpose of keeping “versions open” based on a subset of fields in the parent link.
Example: A Data Vault model that has a link between a Customer and a Contact. It is required (for this specific example) to keep only one contact, per customer open at a given point in time. This means that, if a customer changes contacts, only the latest relationship between the Customer and its Contact is kept as an open relationship. Hub Customer’s hashkey would be the driving key.
- __init__(schema, name, fields, driving_keys, *args, **kwargs)¶
Instantiate an EffectivitySatellite.
str) – Data Vault schema name.
str) – Satellite name.
Field]) – List of fields that this Satellite holds.
DrivingKeyField]) – Define the set of link (parent table) fields that should be used as driving keys (in the example presented above, the driving key would be the h_customer_hashkey).
args – Unused here, useful for children classes.
kwargs – Unused here, useful for children classes.
- property sql_load_statement: str¶
Get the SQL query to populate current effectivity satellite.
All needed placeholders are calculated, in order to match template SQL (check template_sql.effectivity_satellite_dml.sql).
- Return type:
SQL query to load target satellite.
- property sql_placeholders: Dict[str, str]¶
Calculate effectivity satellite specific placeholders.
They are needed to generate SQL.
The results are joined with the results from super().sql_placeholders(), as all placeholders calculated in Satellite (parent class) are applicable in an EffectivitySatellite.
- Return type:
- Effectivity satellite specific placeholders, to use in effectivity