Configures each instance of persistent type to be unique for the combination of properties.
Adding this metadata to a persistent type requires that all instances of this type
must be unique for the combined properties in properties. properties must contain symbolic names of
properties declared in the persistent type, and those properties must be either attributes
or belongs-to relationship properties. See ManagedTableAttributes for example.
Source
const ManagedTableAttributes.unique(List<Symbol> properties) : this(uniquePropertySet: properties);