Effectivity Satellites

Links tell you that a relationship exists. Effectivity satellites tell you when it was active. They track the start and end dates of relationships between entities.

What an Eff Sat Contains

• Link hash key (FK) — which relationship this tracks
• Start date — when the relationship became active
• End date — when it ended (or 9999-12-31 if still active)
• Load datetime — when this record was loaded

Eff Sat Models in This Pipeline

eff_sat_order_customer       — is this customer still associated with this order?
eff_sat_order_line_order     — is this line item still on this order?
eff_sat_order_line_product   — is this product still on this line item?

When Do Relationships End?

In FMCG, relationships can change:

• An order gets cancelled — the order-customer relationship ends
• A line item is removed from an order — the line-order relationship ends
• A product is substituted on a line item — the old product link ends, a new one starts

Why Not Just Use Satellites?

Regular satellites track attribute changes on a single entity. Effectivity satellites track the validity period of a relationship between two entities. They answer a different question: not "what changed?" but "was this active on March 15?"

Bridge and PIT Dependency

Effectivity satellites feed into PITs and Bridges downstream. The bridge table uses eff sats to filter only active relationships when building the pre-joined result set.