Stage S

Span

SP_CORE_SPAN

Span represents many as one, then answers as-is, as-was, as-was-at. It is read-only projection over Conform facts and Identity enrichment — no new business semantics. Restatement is not audit; counterfactual clustering is not a consumer API.

Where Span sits in CRISP

Rendering diagram…

Highlighted: Span represents many as one and projects time.

How does Span use Identity?

How Span is formed from Identity

Identity owns clustering and winner election (rules, exceptions, optional hints). Span projects those outcomes onto consume_*_key, cluster_role, and winner-facing columns — it does not re-run match logic or invent a second truth.

Identity rules → Span projection

Same teaching example as on Extensions: Northbridge Marine across billing vendors (A / B shown; more lanes follow the same Identity → Span path).

Native A · Conform

SYS_A:AH-77421

NORTHBRIDGE MARINE LTD

valid_from: 2019-03-01

Native B · Conform

SYS_B:BP-99102

Northbridge Marine Limited

valid_from: 2021-06-14

Identity · rules + exceptions

Cluster rule — match key folds LTD↔LIMITED + party_kind → one hub, two members
Winner rule — winner_rank = valid_from ASC → A is WINNER, B is MEMBER
Exceptions (when authored) — steward merge / force-discrete / equivalence can override before election

Span · PARTY (projected)

consume_party_key

CPT-NORTHBRIDGE-01

= COALESCE(cluster_party_key, party_header_key)

display_name ← winner

Northbridge Marine Ltd

A won on earliest valid_from

Members stay addressable (native grain / participants). Lane-only fields such as B’s lei ride in extensions — see Extensions.

Span does not invent sameness or winners — it projects Identity outcomes onto consume keys. Cluster match, winner election, and exceptions live in Identity rules.

Projection from Identity outcomes

# Identity already materialised
#   hub + members · cluster_role ∈ {WINNER, MEMBER}
#   winner_rank e.g. valid_from ASC (steward exceptions override)

consume_party_key(row) =
  COALESCE(row.cluster_party_key, row.party_header_key)

# Span.PARTY — enrich open Conform with Identity
SPAN.PARTY =
  conform_open(PARTY)
  LEFT JOIN identity_members
  SELECT
    consume_party_key,
    cluster_role,
    display_name,          # winner facade when clustered
    … typed canon columns,
    extensions             # participants / lane bag — see Extensions

# Collapsed consumer grain (often via Publish) uses consume_party_key
# Native grain keeps every member row for drill-down

For the full story of lane-only fields on participants (e.g. reading System B’s lei after collapse), see Extensions. Identity rule authorship lives on Identity.

How do you read as-is, as-was, as-was-at? Learn more about Extensions

Four surfaces — many as one, then three reads

Identity determines the match; Span projects it onto consume keys and temporal families. One consumer API cannot honestly answer “now”, “business-true at T”, and “what did we show in window W” with the same filter.

COALESCE · Many as one

Many as one

consume_{subject}_key = COALESCE(cluster, header)

How do many native rows become one subject for reporting?

Join Conform to Identity enrichment. Clustered natives share a consume key; singletons fall back to the header key.

three PAS parties → one consume_party_key

Representation for query — Identity already decided the match; Span projects it.

READ · AS_IS

AS_IS

SPAN.{entity}_AS_IS (views)

What do we believe now?

Current open Conform assertion (system_to IS NULL) joined to current open Identity hub. Everyday BI.

PARTY_AS_IS · consume_party_key = CP-77

Non-parameterised views — “today’s open facts + today’s clustering”.

READ · AS_WAS

AS_WAS

SPAN.{entity}_AS_WAS(business_ts)

What was business-true at T, knowing what we know now?

Slice Conform on valid_* at T; join current open Identity hub. Restatement — not “cluster as of T”.

AS_WAS('2024-06-30') on POLICY

Today’s clusters applied to the mid-year business slice — not a re-run of match rules at T.

READ · AS_WAS_AT

AS_WAS_AT

SPAN.{entity}_AS_WAS_AT(start, end)

Why did the platform show X in window W?

Conform overlapping W on system_* plus Identity hubs whose warehouse_* overlapped W. Close-day defence.

AS_WAS_AT('2024-03-01', '2024-03-08')

A Wednesday correction does not rewrite Monday’s AS_WAS_AT replay.

Counterfactual re-cluster at T is a governed rebuild-at-cut job — not a view. After CORE uplift, AS_WAS_AT also has an archive mode for literal old shape — see Evolution. Publish freezes consumer names and KPIs over these projections.

What do the reads look like in code? Learn more about Evolution

Pseudocode

Coalesce + temporal families

# Many as one — Identity enrich on Conform
consume_key(row) =
  COALESCE(row.cluster_{subject}_key, row.{subject}_header_key)

# Everyday — non-parameterised views
AS_IS(entity) =
  conform_open(entity)                    # system_to IS NULL
  LEFT JOIN identity_open
  ON consume_key

# Restatement — business time + today's clustering
AS_WAS(entity, business_ts) =
  conform WHERE valid_from <= business_ts < valid_to
  JOIN current_cluster                    # NOT cluster-as-of-T

# Audit — what the platform believed in window W
AS_WAS_AT(entity, audit_start, audit_end) =
  conform overlapping W on system_*
  JOIN Identity hubs whose warehouse_* overlapped W
  ON uplifted current-shape chain

# Counterfactual re-cluster at T → governed rebuild job, not a view

Next: Publish