Trait UntypedExpressionMethods 

pub trait UntypedExpressionMethods: Sized {
    // Provided methods
    fn is_null(self) -> IsNull<Self> { ... }
    fn is_not_null(self) -> IsNotNull<Self> { ... }
    fn desc(self) -> Desc<Self> { ... }
    fn asc(self) -> Asc<Self> { ... }
}

Methods present on untyped expressions.

This trait is implemented for expressions where the sql type is Untyped. This allows calling common operators on these expressions.

This trait is primarily meant to be used for untyped queries in diesel_dynamic_schema.

Provided Methods

fn is_null(self) -> IsNull<Self>

Creates a SQL IS NULL expression.

Example

use diesel::sql_types::Untyped;
use diesel::dsl::sql;

let data = animals
    .select(species)
    .filter(sql::<Untyped>("name").is_null())
    .first::<String>(connection)?;
assert_eq!("spider", data);

fn is_not_null(self) -> IsNotNull<Self>

Creates a SQL IS NOT NULL expression.

Example

use diesel::sql_types::Untyped;
use diesel::dsl::sql;

let data = animals
    .select(species)
    .filter(sql::<Untyped>("name").is_not_null())
    .first::<String>(connection)?;
assert_eq!("dog", data);

fn desc(self) -> Desc<Self>

Creates a SQL DESC expression, representing this expression in descending order.

Example

use diesel::sql_types::Untyped;
use diesel::dsl::sql;

let data = users
    .select(name)
    .order(sql::<Untyped>("name").desc())
    .load::<String>(connection)?;
let expected = vec!["Tess", "Sean"];
assert_eq!(expected, data);

fn asc(self) -> Asc<Self>

Creates a SQL ASC expression, representing this expression in ascending order.

Example

use diesel::sql_types::Untyped;
use diesel::dsl::sql;

let data = users
    .select(name)
    .order(sql::<Untyped>("name").asc())
    .load::<String>(connection)?;
let expected = vec!["Sean", "Tess"];
assert_eq!(expected, data);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> UntypedExpressionMethods for T

where T: Expression<SqlType = Untyped>,