Metamodel — `dimension` types

Each section below is one dimension.<subType>. The Attributes table lists the subtype's own + concern-contributed attributes (provider-tagged); universal documentation attributes are omitted here (see providers.md). Allowed children lists the structural child rules with their cardinality (min..max, * = unbounded).

dimension.attribute

A named group-by attribute of the entity that declares it (FR-044). Groups report rows by a column value as-is. @of names Entity.field: the owning entity, or the @via terminal. @via may follow only to-one hops, so grouping by a related row's column can never multiply the measured rows.

When to use: A column a dashboard groups by: product, status, region. Declare it once on the fact entity and reference it by name from reports.

Attributes

Attribute	Type	Required	Default	Allowed values	Provider	Description
`@of`	string	yes			—	Dotted Entity.field reference naming the grouped column (e.g. 'Purchase.programId', or 'Program.title' with @via).
`@via`	string	no			—	Optional dotted to-one relationship path from the owning entity to the entity @of names (e.g. 'Purchase.program'). Every hop must be @cardinality: one or an identity.reference.

Allowed children

No structural children.

dimension.time

A named time dimension (FR-044): groups report rows by a date or timestamp column truncated to a grain. @of names a field.date or field.timestamp. Weeks start on Monday (ISO-8601) in every lowering. A report names it as 'dimension:grain' and the derived report field is (e.g. purchasedAtDay).

When to use: Per-day, per-week or per-month series on a dashboard.