Trait ActiveEnum

Source

pub trait ActiveEnum: Sized + Iterable {
    type Value: ActiveEnumValue;
    type ValueVec;

    // Required methods
    fn name() -> DynIden;
    fn to_value(&self) -> Self::Value;
    fn try_from_value(v: &Self::Value) -> Result<Self, DbErr>;
    fn db_type() -> ColumnDef;

    // Provided methods
    fn into_value(self) -> Self::Value { ... }
    fn as_enum(&self) -> SimpleExpr { ... }
    fn values() -> Vec<Self::Value> { ... }
}

Expand description

A Rust representation of enum defined in database.

§Implementations

You can implement ActiveEnum manually by hand or use the derive macro DeriveActiveEnum.

§Examples

Implementing it manually versus using the derive macro DeriveActiveEnum.

See DeriveActiveEnum for the full specification of macro attributes.

use sea_orm::entity::prelude::*;

// Using the derive macro
#[derive(Debug, PartialEq, EnumIter, DeriveActiveEnum, DeriveDisplay)]
#[sea_orm(
    rs_type = "String",
    db_type = "String(StringLen::N(1))",
    enum_name = "category"
)]
pub enum DeriveCategory {
    #[sea_orm(string_value = "B")]
    Big,
    #[sea_orm(string_value = "S")]
    Small,
}

// Implementing it manually
#[derive(Debug, PartialEq, EnumIter)]
pub enum Category {
    Big,
    Small,
}

#[derive(Debug, DeriveIden)]
pub struct CategoryEnum;

impl ActiveEnum for Category {
    // The macro attribute `rs_type` is being pasted here
    type Value = String;

    type ValueVec = Vec<String>;

    // Will be atomically generated by `DeriveActiveEnum`
    fn name() -> DynIden {
        SeaRc::new(CategoryEnum)
    }

    // Will be atomically generated by `DeriveActiveEnum`
    fn to_value(&self) -> Self::Value {
        match self {
            Self::Big => "B",
            Self::Small => "S",
        }
        .to_owned()
    }

    // Will be atomically generated by `DeriveActiveEnum`
    fn try_from_value(v: &Self::Value) -> Result<Self, DbErr> {
        match v.as_ref() {
            "B" => Ok(Self::Big),
            "S" => Ok(Self::Small),
            _ => Err(DbErr::Type(format!(
                "unexpected value for Category enum: {}",
                v
            ))),
        }
    }

    fn db_type() -> ColumnDef {
        // The macro attribute `db_type` is being pasted here
        ColumnType::String(StringLen::N(1)).def()
    }
}

Using ActiveEnum on Model.

use sea_orm::entity::prelude::*;

// Define the `Category` active enum
#[derive(Debug, Clone, PartialEq, EnumIter, DeriveActiveEnum, DeriveDisplay)]
#[sea_orm(rs_type = "String", db_type = "String(StringLen::N(1))")]
pub enum Category {
    #[sea_orm(string_value = "B")]
    Big,
    #[sea_orm(string_value = "S")]
    Small,
}

#[derive(Clone, Debug, PartialEq, DeriveEntityModel)]
#[sea_orm(table_name = "active_enum")]
pub struct Model {
    #[sea_orm(primary_key)]
    pub id: i32,
    // Represents a db column using `Category` active enum
    pub category: Category,
    pub category_opt: Option<Category>,
}

#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
pub enum Relation {}

impl ActiveModelBehavior for ActiveModel {}