Enum Cardinality 

pub enum Cardinality {
    M2O {
        constraint: CompactString,
        columns: SmallVec<[(CompactString, CompactString); 2]>,
    },
    O2M {
        constraint: CompactString,
        columns: SmallVec<[(CompactString, CompactString); 2]>,
    },
    O2O {
        constraint: CompactString,
        columns: SmallVec<[(CompactString, CompactString); 2]>,
        is_parent: bool,
    },
    M2M(Junction),
}

Relationship cardinality

Describes the cardinality of a relationship between two tables.

Variants

M2O

Many-to-One: the source table has an FK pointing to the target’s PK

Following this relationship from source yields at most one target row.

Fields

constraint: CompactString

Foreign key constraint name

columns: SmallVec<[(CompactString, CompactString); 2]>

Column mappings: (source_column, target_column)

O2M

One-to-Many: the source table’s PK is referenced by the target’s FK

Following this relationship from source yields potentially many target rows.

Fields

constraint: CompactString

Foreign key constraint name (on the target table)

columns: SmallVec<[(CompactString, CompactString); 2]>

Column mappings: (source_column, target_column)

O2O

One-to-One: like M2O but the FK columns are also unique

Following this relationship from either side yields at most one row.

Fields

constraint: CompactString

Foreign key constraint name

columns: SmallVec<[(CompactString, CompactString); 2]>

Column mappings: (source_column, target_column)

is_parent: bool

Whether this is the parent side (referenced) or child side (referencing)

M2M(Junction)

Many-to-Many: relationship via a junction table

Both tables are connected through an intermediate junction table.

Implementations

impl Cardinality

pub fn as_str(&self) -> &'static str

Get a short string representation of this cardinality

Trait Implementations

impl Clone for Cardinality

fn clone(&self) -> Cardinality

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Cardinality

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.