Struct Parameters 

pub struct Parameters { /* private fields */ }

What a prepared statement was handed, by identifier.

A parameter is written ?, ?1, $1 or $name, and the parser gives every one of them an identifier: the number for a positional parameter, the word for a named one, and the position for a bare ?. So a set of values is a list of identifier and value pairs whatever the statement was written with, and there is one lookup rather than two.

A list rather than a map. There are a handful of parameters in a statement, never a thousand, and keeping the order they were given in is worth more here than a hash: it is what the error about unused values lists them in.

Implementations

impl Parameters

pub const fn new() -> Self

No values, which is what an ordinary statement binds with.

pub fn positional(values: Vec<Value>) -> Self

Values by position, numbered from one, which is what ? and $1 want.

pub fn set(&mut self, name: impl Into<String>, value: Value)

Gives one parameter a value, replacing whatever it had.

pub fn get(&self, name: &str) -> Option<&Value>

What one parameter was given, if it was given anything.

pub fn is_empty(&self) -> bool

Whether nothing was provided.

pub fn len(&self) -> usize

How many were provided.

pub fn names(&self) -> impl Iterator<Item = &str>

The identifiers, in the order they were given.

Trait Implementations

impl Clone for Parameters

fn clone(&self) -> Parameters

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Parameters

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

Formats the value using the given formatter.

impl Default for Parameters

fn default() -> Parameters

Returns the “default value” for a type.

impl PartialEq for Parameters

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Parameters