UniverseMembership

close: schema:OrganizationRole

Dated membership of a market universe, INCLUDING delisted and suspended issuers, which are retained permanently. This is the survivorship-bias control: a universe file holding only today's members would report the same count for every past date and silently exclude every company that failed.

Slots

slot	range		description
`dataco_id`	`string`	required	Certvas entity identifier — a deterministic hash of the LEI where one exists, else a ULID. Stable across rebuilds, which is what lets it be a public, citable identifier.
`universe_code`	`string`	required	Which universe this membership is in (for example a market or index code).
`membership_status`	`string`	required	Membership state over the interval — for example active, suspended or delisted.
`status_from`	`date`	optional	Start of the status interval. NULL means the status began at an unknown EARLIER date — an open-left interval, not missing data. A query that drops the null branch silently deletes every issuer whose listing date is unknown from every historical universe.
`status_to`	`date`	optional	End of the status interval; NULL means still in this status.
`history_truncated`	`boolean`	optional	True where the universe is complete FORWARD from first observation but not backward. Flagged rather than left implicit, because implied completeness is the bias this table exists to remove.
`observed_at`	`datetime`	required	When Certvas itself observed this value. Never a proxy for publication date.
`source_ref`	`string`	required	URL or document-hash pointer into the immutable raw archive.
`license_class`	`string`	required	License Register ID governing redistribution of THIS row. Per-row rather than per-table because a single table legitimately mixes sources with different terms.
`valid_from`	`date`	required	Start of the interval over which this assertion holds.
`valid_to`	`date`	optional	End of the validity interval; NULL means current. Half-open, so `valid_from <= t < valid_to` selects without double-counting the boundary.