Struct Schema 

pub struct Schema { /* private fields */ }

An ordered list of top-level fields, optionally named (a table, a record type, a document), and the further tables a schema of several holds (SQL DDL’s CREATE TABLEs).

Keys that span columns (a composite primary key, UNIQUE (a, b), a FOREIGN KEY) are the schema’s own constraints; a key on one column is that field’s.

Implementations

impl Schema

pub fn new(fields: impl IntoIterator<Item = Field>) -> Self

A schema of fields, in order.

pub fn of_tables(tables: impl IntoIterator<Item = Schema>) -> Self

A schema of tables, with no fields of its own.

pub fn named(self, name: impl Into<String>) -> Self

Name the schema (a table or type name).

pub fn with_description(self, description: impl Into<String>) -> Self

Describe the schema.

pub fn with_constraint(self, constraint: Constraint) -> Self

Add a table-level constraint.

pub fn with_metadata( self, key: impl Into<String>, value: impl Into<String>, ) -> Self

Add a metadata entry (Arrow’s schema metadata).

pub fn truncated(self, truncated: bool) -> Self

Mark the schema as cut short by a reader’s limit.

pub fn name(&self) -> Option<&str>

The name, if any.

pub fn description(&self) -> Option<&str>

The description, if any.

pub fn fields(&self) -> &[Field]

The top-level fields, in order.

pub fn fields_mut(&mut self) -> &mut Vec<Field>

The top-level fields, to change in place.

pub fn push(&mut self, field: Field) -> &mut Self

Append a field.

pub fn field(&self, name: &str) -> Option<&Field>

The first top-level field called name.

pub fn index_of(&self, name: &str) -> Option<usize>

The position of the first top-level field called name.

pub fn len(&self) -> usize

The number of top-level fields.

pub fn is_empty(&self) -> bool

Whether there are no fields.

pub fn constraints(&self) -> &[Constraint]

The table-level constraints.

pub fn constraints_mut(&mut self) -> &mut Vec<Constraint>

The table-level constraints, to change in place.

pub fn primary_key(&self) -> Vec<&str>

The primary key’s columns: the table’s key when it spans columns, else every field marked as one.

pub fn foreign_keys(&self) -> Vec<ForeignKey>

Every foreign key: the table’s, then each column’s (with the column filled in).

pub fn tables(&self) -> &[Schema]

The further tables the schema holds.

pub fn tables_mut(&mut self) -> &mut Vec<Schema>

The further tables, to change in place.

pub fn push_table(&mut self, table: Schema) -> &mut Self

Add a table.

pub fn table(&self, name: &str) -> Option<&Schema>

The table called name.

pub fn metadata(&self) -> &[(String, String)]

The metadata entries, in order.

pub fn is_truncated(&self) -> bool

Whether a reader’s limit cut the schema short.

Trait Implementations

impl Clone for Schema

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Schema

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

Formats the value using the given formatter.

impl Default for Schema

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Schema

impl FromIterator<Field> for Schema

fn from_iter<I: IntoIterator<Item = Field>>(iter: I) -> Self

Creates a value from an iterator.

impl Hash for Schema

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 PartialEq for Schema

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Schema