Trait PgExpressionMethods

pub trait PgExpressionMethods: Expression + Sized {
    // Provided methods
    fn is_not_distinct_from<T>(self, other: T) -> IsNotDistinctFrom<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Self::SqlType> { ... }
    fn is_distinct_from<T>(self, other: T) -> IsDistinctFrom<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Self::SqlType> { ... }
    fn is_contained_by_range<T>(self, other: T) -> IsContainedByRange<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Range<Self::SqlType>> { ... }
}

Available on crate feature postgres_backend only.

PostgreSQL specific methods which are present on all expressions.

Provided Methods

fn is_not_distinct_from<T>(self, other: T) -> IsNotDistinctFrom<Self, T>

where Self::SqlType: SqlType, T: AsExpression<Self::SqlType>,

Creates a PostgreSQL IS NOT DISTINCT FROM expression.

This behaves identically to the = operator, except that NULL is treated as a normal value.

Example

let distinct = users.select(id).filter(name.is_distinct_from("Sean"));
let not_distinct = users.select(id).filter(name.is_not_distinct_from("Sean"));
assert_eq!(Ok(2), distinct.first(connection));
assert_eq!(Ok(1), not_distinct.first(connection));

fn is_distinct_from<T>(self, other: T) -> IsDistinctFrom<Self, T>

where Self::SqlType: SqlType, T: AsExpression<Self::SqlType>,

Creates a PostgreSQL IS DISTINCT FROM expression.

This behaves identically to the != operator, except that NULL is treated as a normal value.

Example

let distinct = users.select(id).filter(name.is_distinct_from("Sean"));
let not_distinct = users.select(id).filter(name.is_not_distinct_from("Sean"));
assert_eq!(Ok(2), distinct.first(connection));
assert_eq!(Ok(1), not_distinct.first(connection));

fn is_contained_by_range<T>(self, other: T) -> IsContainedByRange<Self, T>

where Self::SqlType: SqlType, T: AsExpression<Range<Self::SqlType>>,

Creates a PostgreSQL <@ expression.

This operator returns true whether a element is contained by a range

This operator evaluates to true for the following cases:

self:     |
other:  [-----]

self:  |
other: [----]

self:       |
other:  [----]

This operator evaluates to false for the following cases:

self:           |
other:  [-----]

self:  |
other:   [----]

self:       |
other: [----)

Example

      let my_range = int4range(1, 5, diesel::sql_types::RangeBound::LowerBoundInclusiveUpperBoundExclusive);

      let (first, second) = diesel::select((
          4.into_sql::<Integer>().is_contained_by_range(my_range),
          10.into_sql::<Integer>().is_contained_by_range(my_range)
      )).get_result::<(bool, bool)>(conn)?;

      assert_eq!(first, true);
      assert_eq!(second, false);

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: Expression> PgExpressionMethods for T