Trait ExpressionMethods

pub trait ExpressionMethods: Expression + Sized {
    // Provided methods
    fn eq<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> Eq<Self, T::Expression> { ... }
    fn ne<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> NotEq<Self, T::Expression> { ... }
    fn eq_any<T>(self, values: T) -> In<Self, T::InExpression>
       where T: AsInExpression<Self::SqlType> { ... }
    fn ne_any<T>(self, values: T) -> NotIn<Self, T::InExpression>
       where T: AsInExpression<Self::SqlType> { ... }
    fn ne_all<T>(self, values: T) -> NotIn<Self, T::InExpression>
       where T: AsInExpression<Self::SqlType> { ... }
    fn is_null(self) -> IsNull<Self> { ... }
    fn is_not_null(self) -> IsNotNull<Self> { ... }
    fn gt<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> Gt<Self, T::Expression> { ... }
    fn ge<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> GtEq<Self, T::Expression> { ... }
    fn lt<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> Lt<Self, T::Expression> { ... }
    fn le<T: AsExpression<Self::SqlType>>(
        self,
        other: T,
    ) -> LtEq<Self, T::Expression> { ... }
    fn between<T, U>(
        self,
        lower: T,
        upper: U,
    ) -> Between<Self, And<T::Expression, U::Expression>>
       where T: AsExpression<Self::SqlType>,
             U: AsExpression<Self::SqlType> { ... }
    fn not_between<T, U>(
        self,
        lower: T,
        upper: U,
    ) -> NotBetween<Self, And<T::Expression, U::Expression>>
       where T: AsExpression<Self::SqlType>,
             U: AsExpression<Self::SqlType> { ... }
    fn desc(self) -> Desc<Self> { ... }
    fn asc(self) -> Asc<Self> { ... }
}

Methods present on all expressions, except tuples

Provided Methods

fn eq<T: AsExpression<Self::SqlType>>(self, other: T) -> Eq<Self, T::Expression>

Creates a SQL = expression.

Example

let data = users.select(id).filter(name.eq("Sean"));
assert_eq!(Ok(1), data.first(&connection));

fn ne<T: AsExpression<Self::SqlType>>( self, other: T, ) -> NotEq<Self, T::Expression>

Creates a SQL != expression.

Example

let data = users.select(id).filter(name.ne("Sean"));
assert_eq!(Ok(2), data.first(&connection));

fn eq_any<T>(self, values: T) -> In<Self, T::InExpression>

where T: AsInExpression<Self::SqlType>,

Creates a SQL IN statement.

Queries using this method will not be placed in the prepared statement cache. On PostgreSQL, you should use eq(any()) instead. This method may change in the future to automatically perform = ANY on PostgreSQL.

Example

let data = users.select(id).filter(name.eq_any(vec!["Sean", "Jim"]));
assert_eq!(Ok(vec![1, 3]), data.load(&connection));

// Calling `eq_any` with an empty array is the same as doing `WHERE 1=0`
let data = users.select(id).filter(name.eq_any(Vec::<String>::new()));
assert_eq!(Ok(vec![]), data.load::<i32>(&connection));

fn ne_any<T>(self, values: T) -> NotIn<Self, T::InExpression>

where T: AsInExpression<Self::SqlType>,

👎Deprecated since 1.2.0: use ne_all instead

Deprecated alias for ne_all

let data = users.select(id).filter(name.ne_any(vec!["Sean", "Jim"]));
assert_eq!(Ok(vec![2]), data.load(&connection));

let data = users.select(id).filter(name.ne_any(vec!["Tess"]));
assert_eq!(Ok(vec![1, 3]), data.load(&connection));

// Calling `ne_any` with an empty array is the same as doing `WHERE 1=1`
let data = users.select(id).filter(name.ne_any(Vec::<String>::new()));
assert_eq!(Ok(vec![1, 2, 3]), data.load(&connection));

fn ne_all<T>(self, values: T) -> NotIn<Self, T::InExpression>

where T: AsInExpression<Self::SqlType>,

Creates a SQL NOT IN statement.

Queries using this method will not be placed in the prepared statement cache. On PostgreSQL, you should use ne(all()) instead. This method may change in the future to automatically perform != ALL on PostgreSQL.

Example

let data = users.select(id).filter(name.ne_all(vec!["Sean", "Jim"]));
assert_eq!(Ok(vec![2]), data.load(&connection));

let data = users.select(id).filter(name.ne_all(vec!["Tess"]));
assert_eq!(Ok(vec![1, 3]), data.load(&connection));

// Calling `ne_any` with an empty array is the same as doing `WHERE 1=1`
let data = users.select(id).filter(name.ne_all(Vec::<String>::new()));
assert_eq!(Ok(vec![1, 2, 3]), data.load(&connection));

fn is_null(self) -> IsNull<Self>

Creates a SQL IS NULL expression.

Example

let data = animals
    .select(species)
    .filter(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

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

fn gt<T: AsExpression<Self::SqlType>>(self, other: T) -> Gt<Self, T::Expression>

Creates a SQL > expression.

Example

let data = users
    .select(name)
    .filter(id.gt(1))
    .first::<String>(&connection)?;
assert_eq!("Tess", data);

fn ge<T: AsExpression<Self::SqlType>>( self, other: T, ) -> GtEq<Self, T::Expression>

Creates a SQL >= expression.

Example

let data = users
    .select(name)
    .filter(id.ge(2))
    .first::<String>(&connection)?;
assert_eq!("Tess", data);

fn lt<T: AsExpression<Self::SqlType>>(self, other: T) -> Lt<Self, T::Expression>

Creates a SQL < expression.

Example

let data = users
    .select(name)
    .filter(id.lt(2))
    .first::<String>(&connection)?;
assert_eq!("Sean", data);

fn le<T: AsExpression<Self::SqlType>>( self, other: T, ) -> LtEq<Self, T::Expression>

Creates a SQL <= expression.

Example

let data = users
    .select(name)
    .filter(id.le(2))
    .first::<String>(&connection)?;
assert_eq!("Sean", data);

fn between<T, U>( self, lower: T, upper: U, ) -> Between<Self, And<T::Expression, U::Expression>>

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

Creates a SQL BETWEEN expression using the given lower and upper bounds.

Example

let data = animals
    .select(species)
    .filter(legs.between(2, 6))
    .first(&connection);
assert_eq!(Ok("dog".to_string()), data);

fn not_between<T, U>( self, lower: T, upper: U, ) -> NotBetween<Self, And<T::Expression, U::Expression>>

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

Creates a SQL NOT BETWEEN expression using the given lower and upper bounds.

Example

let data = animals
    .select(species)
    .filter(legs.not_between(2, 6))
    .first::<String>(&connection)?;
assert_eq!("spider", data);

fn desc(self) -> Desc<Self>

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

Example

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

fn asc(self) -> Asc<Self>

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

This is the same as leaving the direction unspecified. It is useful if you need to provide an unknown ordering, and need to box the return value of a function.

Example

let ordering: Box<BoxableExpression<users, DB, SqlType=()>> =
    if order == "name" {
        Box::new(name.desc())
    } else {
        Box::new(id.asc())
    };

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> ExpressionMethods for T

where T: Expression, T::SqlType: SingleValue,