ducklake_view_column_tag

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Documentation / Specification / Tables

View columns can also have tags, which are defined in this table. View column tags require DuckLake format version 1.1.

Column name	Column type
`view_id`	`BIGINT`
`column_name`	`VARCHAR`
`begin_snapshot`	`BIGINT`
`end_snapshot`	`BIGINT`
`key`	`VARCHAR`
`value`	`VARCHAR`

view_id refers to a view_id from the ducklake_view table.
column_name is the name of the view column as produced by the view's query, before the view's column_aliases are applied. For example, for CREATE VIEW v (x) AS SELECT id FROM t, a comment on x is stored with column_name id. View columns are identified by name rather than by a column_id.
begin_snapshot refers to a snapshot_id from the ducklake_snapshot table. The tag is valid starting with this snapshot id.
end_snapshot refers to a snapshot_id from the ducklake_snapshot table. The tag is valid up to but not including this snapshot id. If end_snapshot is NULL, the tag is currently valid.
key is the tag key and cannot be NULL. DuckDB stores SQL comments under the comment key.
value is the tag value.

Replacing a tag ends the previous tag version and creates a new one. Dropping a view ends its column tags. Expiring snapshots removes tag versions that are no longer visible in any retained snapshot.

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