Enumeration
You can use Rust enums in model where the values are mapped to a database string, integer or native enum.
String
#[derive(EnumIter, DeriveActiveEnum)]
#[sea_orm(rs_type = "String", db_type = "String(Some(1))")]
pub enum Category {
#[sea_orm(string_value = "B")]
Big,
#[sea_orm(string_value = "S")]
Small,
}Integer
#[derive(EnumIter, DeriveActiveEnum)]
#[sea_orm(rs_type = "i32", db_type = "Integer")]
pub enum Color {
#[sea_orm(num_value = 0)]
Black,
#[sea_orm(num_value = 1)]
White,
}Alternatively, you could write:
#[derive(EnumIter, DeriveActiveEnum)]
#[sea_orm(rs_type = "i32", db_type = "Integer")]
pub enum Color {
Black = 0,
White = 1,
}Native Database Enum
#[derive(EnumIter, DeriveActiveEnum)]
#[sea_orm(rs_type = "String", db_type = "Enum", enum_name = "tea")]
pub enum Tea {
#[sea_orm(string_value = "EverydayTea")]
EverydayTea,
#[sea_orm(string_value = "BreakfastTea")]
BreakfastTea,
}
Implementations
You can implement ActiveEnum
manually by hand or use the derive macro DeriveActiveEnum
.
Derive Implementation
See DeriveActiveEnum
for the full specification of macro attributes.
use sea_orm::entity::prelude::*;
// Using the derive macro
#[derive(Debug, PartialEq, EnumIter, DeriveActiveEnum)]
#[sea_orm(
rs_type = "String",
db_type = "String(Some(1))",
enum_name = "category"
)]
pub enum Category {
#[sea_orm(string_value = "B")]
Big,
#[sea_orm(string_value = "S")]
Small,
}
Manual Implementation
use sea_orm::entity::prelude::*;
// Implementing it manually
#[derive(Debug, PartialEq, EnumIter)]
pub enum Category {
Big,
Small,
}
impl ActiveEnum for Category {
// The macro attribute `rs_type` is being pasted here
type Value = String;
// By default, the name of Rust enum in camel case if `enum_name` was not provided explicitly
fn name() -> String {
"category".to_owned()
}
// Map Rust enum variants to corresponding `num_value` or `string_value`
fn to_value(&self) -> Self::Value {
match self {
Self::Big => "B",
Self::Small => "S",
}
.to_owned()
}
// Map `num_value` or `string_value` to corresponding Rust enum variants
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
))),
}
}
// The macro attribute `db_type` is being pasted here
fn db_type() -> ColumnDef {
ColumnType::String(Some(1)).def()
}
}
Using ActiveEnum on Model
use sea_orm::entity::prelude::*;
// Define the `Category` active enum
#[derive(Debug, Clone, PartialEq, EnumIter, DeriveActiveEnum)]
#[sea_orm(rs_type = "String", db_type = "String(Some(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 {}