columns property
The columns of the table that should be part of the index.
This can either be a Symbol for the default options or an IndexedColumn instance.
Columns are referenced with a Symbol of their getter name used in the
column definition. For instance, a table declaring a column as
IntColumn get nextUpdateSnapshot => ...()
could reference this column
using #nextUpdateSnapshot
.
To further control options of the index, use an IndexedColumn instance.
Implementation
final Set<Object /*IndexedColumn | Symbol*/ > columns;