Trait diesel::expression_methods::PgArrayExpressionMethods

pub trait PgArrayExpressionMethods: Expression + Sized {
    // Provided methods
    fn overlaps_with<T>(self, other: T) -> OverlapsWith<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Self::SqlType> { ... }
    fn contains<T>(self, other: T) -> ArrayContains<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Self::SqlType> { ... }
    fn is_contained_by<T>(self, other: T) -> IsContainedBy<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Self::SqlType> { ... }
    fn index<T>(self, other: T) -> ArrayIndex<Self, T>
       where Self::SqlType: SqlType,
             T: AsExpression<Integer> { ... }
}

Available on crate feature postgres_backend only.

PostgreSQL specific methods present on array expressions.

Provided Methods

fn overlaps_with<T>(self, other: T) -> OverlapsWith<Self, T>

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

Creates a PostgreSQL && expression.

This operator returns whether two arrays have common elements.

Example

diesel::insert_into(posts)
    .values(&vec![
        tags.eq(vec!["cool", "awesome"]),
        tags.eq(vec!["awesome", "great"]),
        tags.eq(vec!["cool", "great"]),
    ])
    .execute(conn)?;

let data = posts.select(id)
    .filter(tags.overlaps_with(vec!["horrid", "cool"]))
    .load::<i32>(conn)?;
assert_eq!(vec![1, 3], data);

let data = posts.select(id)
    .filter(tags.overlaps_with(vec!["cool", "great"]))
    .load::<i32>(conn)?;
assert_eq!(vec![1, 2, 3], data);

let data = posts.select(id)
    .filter(tags.overlaps_with(vec!["horrid"]))
    .load::<i32>(conn)?;
assert!(data.is_empty());

fn contains<T>(self, other: T) -> ArrayContains<Self, T>

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

Creates a PostgreSQL @> expression.

This operator returns whether an array contains another array.

Example

diesel::insert_into(posts)
    .values(tags.eq(vec!["cool", "awesome"]))
    .execute(conn)?;

let cool_posts = posts.select(id)
    .filter(tags.contains(vec!["cool"]))
    .load::<i32>(conn)?;
assert_eq!(vec![1], cool_posts);

let amazing_posts = posts.select(id)
    .filter(tags.contains(vec!["cool", "amazing"]))
    .load::<i32>(conn)?;
assert!(amazing_posts.is_empty());

fn is_contained_by<T>(self, other: T) -> IsContainedBy<Self, T>

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

Creates a PostgreSQL <@ expression.

This operator returns whether an array is contained by another array. foo.contains(bar) is the same as bar.is_contained_by(foo)

Example

diesel::insert_into(posts)
    .values(tags.eq(vec!["cool", "awesome"]))
    .execute(conn)?;

let data = posts.select(id)
    .filter(tags.is_contained_by(vec!["cool", "awesome", "amazing"]))
    .load::<i32>(conn)?;
assert_eq!(vec![1], data);

let data = posts.select(id)
    .filter(tags.is_contained_by(vec!["cool"]))
    .load::<i32>(conn)?;
assert!(data.is_empty());

fn index<T>(self, other: T) -> ArrayIndex<Self, T>

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

Indexes a PostgreSQL array.

This operator indexes in to an array to access a single element.

Note that PostgreSQL arrays are 1-indexed, so foo.index(1) is the first element in the array.

Example

diesel::insert_into(posts)
    .values(&vec![
        tags.eq(vec!["cool", "awesome"]),
        tags.eq(vec!["splendid", "marvellous"]),
   ])
    .execute(conn)?;

let data = posts.select(tags.index(id))
    .load::<String>(conn)?;
assert_eq!(vec!["cool", "marvellous"], data);

let data = posts.select(id)
    .filter(tags.index(1).eq("splendid"))
    .load::<i32>(conn)?;
assert_eq!(vec![2], data);

Object Safety

This trait is not object safe.

Implementors

impl<T> PgArrayExpressionMethods for T

where T: Expression, T::SqlType: ArrayOrNullableArray,