Struct RelationType

pub struct RelationType {
    pub column_types: Vec<ColumnType>,
    pub keys: Vec<Key>,
    pub time_index: Option<usize>,
    pub auto_columns: Vec<usize>,
}

The type of a relation.

Fields

column_types: Vec<ColumnType>

The type for each column, in order.

keys: Vec<Key>

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.

time_index: Option<usize>

optionally indicate the column that is TIME INDEX

auto_columns: Vec<usize>

mark all the columns that are added automatically by flow, but are not present in original sql

Implementations

impl RelationType

pub fn with_autos(self, auto_cols: &[usize]) -> Self

pub fn apply_mfp(&self, mfp: &SafeMfpPlan) -> Result<Self>

Trying to apply a mpf on current types, will return a new RelationType with the new types, will also try to preserve keys&time index information if the old key&time index columns are preserve in given mfp

i.e. old column of size 3, with a mfp’s

project = [2, 1],

the old key = [1], old time index = [2],

then new key=[1], new time index=[0]

note that this function will remove empty keys like key=[] will be removed

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. Also sorts the key indices.

will ignore empty key

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

Adds new keys for the relation. Also sorts the key indices.

will ignore empty keys

pub fn with_time_index(self, time_index: Option<usize>) -> Self

will also remove time index from keys if it’s in keys

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.

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

True if any collection described by self could safely be described by other.

In practice this means checking that the scalar types match exactly, and that the nullability of self is at least as strict as other, and that all keys of other contain some key of self (as a set of key columns is less strict than any subset).

pub fn into_named(self, names: Vec<Option<String>>) -> RelationDesc

Return relation describe with column names

pub fn into_unnamed(self) -> RelationDesc

Return relation describe without column names

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, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for RelationType

fn cmp(&self, other: &RelationType) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for RelationType

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for RelationType

fn partial_cmp(&self, other: &RelationType) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

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 StructuralPartialEq for RelationType