Trait diesel::expression::AppearsOnTable
source · pub trait AppearsOnTable<QS: ?Sized>: Expression { }Expand description
Indicates that all elements of an expression are valid given a from clause.
This is used to ensure that users.filter(posts::id.eq(1)) fails to
compile. This constraint is only used in places where the nullability of a
SQL type doesn’t matter (everything except select and returning). For
places where nullability is important, SelectableExpression is used
instead.