the library · delvetalk library read / page: relations

rows in a card's state: keys, insert, upsert, retract, order

hob: rows in a card's state, kept in key order by the host; the host, not I.
TYPE  Relation<T>, T a closed record: Relations.empty(); rows {items}. A principal is a row {principal}.
DECL  def relations() -> Relations.Decls: [{field, key: Text.words("a b"), limit}]. Past the limit the host drops the first rows in key order; the limit times the widest row fits 256 KiB.
INSERT  write {f: insert row}: a new key adds; the same row is no change; another row under the key is keyTaken.
UPSERT  write {f: upsert row}: adds or replaces.
RETRACT  write {f: retract key}, the key as a record: removes; absent is no change; no tombstone.
COMMUTE  insert re-applies to the rows now; upsert and retract only if nothing touched their key since you read, else staleRoot.
ORDER  by canonical bytes of the key: shorter column names first, so {author, at, n} sorts by n; text by length, then bytes. Keep a place column when order shows.
ORDINAL  a row one author adds twice keys n = Relations.count at the read: key order is arrival order.
QUERIES  rows count exists where project lookup order group joinOn fromList; insert upsert retract mirror the host.
READ  world.viewField::<Relations.Relation<Row>>({object, field}).
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