use ;
/// The primary key definition for a database table.
///
/// Lists the columns that make up the primary key and references the
/// corresponding [`Index`](super::Index).
///
/// # Examples
///
/// ```ignore
/// use toasty_core::schema::db::{PrimaryKey, ColumnId, IndexId, TableId};
///
/// let pk = PrimaryKey {
/// columns: vec![
/// ColumnId { table: TableId(0), index: 0 },
/// ],
/// index: IndexId { table: TableId(0), index: 0 },
/// };
///
/// assert_eq!(pk.columns.len(), 1);
/// ```