Struct repr::RelationType

pub struct RelationType {
    pub column_types: Vec<ColumnType>,
    pub keys: Vec<Vec<usize>>,
}

The type of a relation.

Fields

column_types: Vec<ColumnType>

The type for each column, in order.

keys: Vec<Vec<usize>>

Sets of indices that are “keys” for the collection.

Each element in this list is a set of column indices, each with the property that the collection contains at most one record with each distinct set of values for each column. Alternately, for a specific set of values assigned to the these columns there is at most one record.

A collection can contain multiple sets of keys, although it is common to have either zero or one sets of key indices.

Implementations

impl RelationType

pub fn empty() -> Self

Constructs a RelationType representing the relation with no columns and no keys.

pub fn new(column_types: Vec<ColumnType>) -> Self

Constructs a new RelationType from specified column types.

The RelationType will have no keys.

pub fn with_key(self, indices: Vec<usize>) -> Self

Adds a new key for the relation.

pub fn with_keys(self, keys: Vec<Vec<usize>>) -> Self

pub fn arity(&self) -> usize

Computes the number of columns in the relation.

pub fn default_key(&self) -> Vec<usize>

Gets the index of the columns used when creating a default index.

Trait Implementations

impl Clone for RelationType

fn clone(&self) -> RelationType

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RelationType

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for RelationType

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error> where
    __D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl Hash for RelationType

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl MzReflect for RelationType

fn add_to_reflected_type_info(rti: &mut ReflectedTypeInfo)

Adds names and types of the fields of the struct or enum to rti.

impl PartialEq<RelationType> for RelationType

fn eq(&self, other: &RelationType) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &RelationType) -> bool

This method tests for !=.

impl Serialize for RelationType

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error> where
    __S: Serializer, 

Serialize this value into the given Serde serializer.

impl Eq for RelationType

impl StructuralEq for RelationType

impl StructuralPartialEq for RelationType