Introduce ARITY to PrimaryKeyTrait

sea-orm-codegen/src/tests_cfg/duplicated_many_to_many_paths/bills.rs

@@ -5,7 +5,7 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: i32,
-    pub user_id: Option<i32> ,
+    pub user_id: Option<i32>,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
@@ -15,7 +15,7 @@ pub enum Relation {
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "NoAction",
-        on_delete = "NoAction",
+        on_delete = "NoAction"
     )]
     Users,
     #[sea_orm(has_many = "super::users_saved_bills::Entity")]

sea-orm-codegen/src/tests_cfg/duplicated_many_to_many_paths/users_saved_bills.rs

@@ -16,15 +16,15 @@ pub enum Relation {
         from = "Column::BillId",
         to = "super::bills::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Bills,
     #[sea_orm(
         belongs_to = "super::users::Entity",
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Users,
 }

sea-orm-codegen/src/tests_cfg/duplicated_many_to_many_paths/users_votes.rs

@@ -17,15 +17,15 @@ pub enum Relation {
         from = "Column::BillId",
         to = "super::bills::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Bills,
     #[sea_orm(
         belongs_to = "super::users::Entity",
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Users,
 }

sea-orm-codegen/src/tests_cfg/many_to_many/bills.rs

@@ -5,7 +5,7 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: i32,
-    pub user_id: Option<i32> ,
+    pub user_id: Option<i32>,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
@@ -15,7 +15,7 @@ pub enum Relation {
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "NoAction",
-        on_delete = "NoAction",
+        on_delete = "NoAction"
     )]
     Users,
     #[sea_orm(has_many = "super::users_votes::Entity")]

sea-orm-codegen/src/tests_cfg/many_to_many/users_votes.rs

@@ -17,15 +17,15 @@ pub enum Relation {
         from = "Column::BillId",
         to = "super::bills::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Bills,
     #[sea_orm(
         belongs_to = "super::users::Entity",
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "Cascade",
-        on_delete = "Cascade",
+        on_delete = "Cascade"
     )]
     Users,
 }

sea-orm-codegen/src/tests_cfg/many_to_many_multiple/bills.rs

@@ -5,7 +5,7 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: i32,
-    pub user_id: Option<i32> ,
+    pub user_id: Option<i32>,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
@@ -15,7 +15,7 @@ pub enum Relation {
         from = "Column::UserId",
         to = "super::users::Column::Id",
         on_update = "NoAction",
-        on_delete = "NoAction",
+        on_delete = "NoAction"
     )]
     Users,
 }

sea-orm-codegen/src/tests_cfg/many_to_many_multiple/users_votes.rs

@@ -7,8 +7,8 @@ pub struct Model {
     pub user_id: i32,
     #[sea_orm(primary_key, auto_increment = false)]
     pub bill_id: i32,
-    pub user_idd: Option<i32> ,
-    pub bill_idd: Option<i32> ,
+    pub user_idd: Option<i32>,
+    pub bill_idd: Option<i32>,
     pub vote: bool,
 }
 
@@ -17,25 +17,25 @@ pub enum Relation {
     #[sea_orm(
         belongs_to = "super::bills::Entity",
         from = "Column::BillIdd",
-        to = "super::bills::Column::Id",
+        to = "super::bills::Column::Id"
     )]
     Bills2,
     #[sea_orm(
         belongs_to = "super::bills::Entity",
         from = "Column::BillId",
-        to = "super::bills::Column::Id",
+        to = "super::bills::Column::Id"
     )]
     Bills1,
     #[sea_orm(
         belongs_to = "super::users::Entity",
         from = "Column::UserIdd",
-        to = "super::users::Column::Id",
+        to = "super::users::Column::Id"
     )]
     Users2,
     #[sea_orm(
         belongs_to = "super::users::Entity",
         from = "Column::UserId",
-        to = "super::users::Column::Id",
+        to = "super::users::Column::Id"
     )]
     Users1,
 }

sea-orm-codegen/src/tests_cfg/self_referencing/bills.rs

@@ -5,16 +5,12 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: i32,
-    pub self_id: Option<i32> ,
+    pub self_id: Option<i32>,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
 pub enum Relation {
-    #[sea_orm(
-        belongs_to = "Entity",
-        from = "Column::SelfId",
-        to = "Column::Id",
-    )]
+    #[sea_orm(belongs_to = "Entity", from = "Column::SelfId", to = "Column::Id")]
     SelfRef,
 }
 

sea-orm-codegen/src/tests_cfg/self_referencing/users.rs

@@ -5,23 +5,15 @@ use sea_orm::entity::prelude::*;
 pub struct Model {
     #[sea_orm(primary_key)]
     pub id: i32,
-    pub self_id: Option<i32> ,
-    pub self_idd: Option<i32> ,
+    pub self_id: Option<i32>,
+    pub self_idd: Option<i32>,
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
 pub enum Relation {
-    #[sea_orm(
-        belongs_to = "Entity",
-        from = "Column::SelfId",
-        to = "Column::Id",
-    )]
+    #[sea_orm(belongs_to = "Entity", from = "Column::SelfId", to = "Column::Id")]
     SelfRef2,
-    #[sea_orm(
-        belongs_to = "Entity",
-        from = "Column::SelfIdd",
-        to = "Column::Id",
-    )]
+    #[sea_orm(belongs_to = "Entity", from = "Column::SelfIdd", to = "Column::Id")]
     SelfRef1,
 }
 

sea-orm-macros/src/derives/entity_model.rs

@@ -308,6 +308,7 @@ pub fn expand_derive_entity_model(data: Data, attrs: Vec<Attribute>) -> syn::Res
 
     let primary_key = {
         let auto_increment = auto_increment && primary_keys.len() == 1;
+        let arity = primary_key_types.len();
         let primary_key_types = if primary_key_types.len() == 1 {
             let first = primary_key_types.first();
             quote! { #first }
@@ -323,6 +324,8 @@ pub fn expand_derive_entity_model(data: Data, attrs: Vec<Attribute>) -> syn::Res
 
             #[automatically_derived]
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = #arity;
+
                 type ValueType = #primary_key_types;
 
                 fn auto_increment() -> bool {

src/entity/column.rs

@@ -727,6 +727,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {
@@ -832,6 +834,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {
@@ -943,6 +947,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {
@@ -1053,6 +1059,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {
@@ -1184,6 +1192,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {
@@ -1322,6 +1332,8 @@ mod tests {
             }
 
             impl PrimaryKeyTrait for PrimaryKey {
+                const ARITY: usize = 1;
+
                 type ValueType = i32;
 
                 fn auto_increment() -> bool {

src/entity/mod.rs

@@ -64,6 +64,8 @@
 ///
 /// // Or implement the [PrimaryKeyTrait] manually instead of using the macro [DerivePrimaryKey]
 /// impl PrimaryKeyTrait for PrimaryKey {
+///     const ARITY: usize = 1;
+///
 ///     type ValueType = i32;
 ///
 ///     fn auto_increment() -> bool {

src/entity/primary_key.rs

@@ -38,7 +38,10 @@ use std::fmt::Debug;
 /// ```
 /// See module level docs [crate::entity] for a full example
 pub trait PrimaryKeyTrait: IdenStatic + Iterable {
-    #[allow(missing_docs)]
+    /// How many columns this Primary Key comprises
+    const ARITY: usize;
+
+    /// Rust Type of the Primary Key
     type ValueType: Sized
         + Send
         + Debug
@@ -48,7 +51,7 @@ pub trait PrimaryKeyTrait: IdenStatic + Iterable {
         + TryGetableMany
         + TryFromU64;
 
-    /// Method to call to perform `AUTOINCREMENT` operation on a Primary Kay
+    /// Method to call to perform `AUTOINCREMENT` operation on a Primary Key
     fn auto_increment() -> bool;
 }
 

src/tests_cfg/cake_expanded.rs

@@ -28,6 +28,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
+
     type ValueType = i32;
 
     fn auto_increment() -> bool {

src/tests_cfg/cake_filling.rs

@@ -29,6 +29,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 2;
+
     type ValueType = (i32, i32);
 
     fn auto_increment() -> bool {

src/tests_cfg/cake_filling_price.rs

@@ -38,6 +38,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 2;
+
     type ValueType = (i32, i32);
 
     fn auto_increment() -> bool {

src/tests_cfg/filling.rs

@@ -40,6 +40,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
+
     type ValueType = i32;
 
     fn auto_increment() -> bool {

src/tests_cfg/indexes.rs

@@ -37,6 +37,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
+
     type ValueType = i32;
 
     fn auto_increment() -> bool {

src/tests_cfg/lunch_set_expanded.rs

@@ -33,6 +33,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
+
     type ValueType = i32;
 
     fn auto_increment() -> bool {

tests/common/features/collection_expanded.rs

@@ -33,6 +33,7 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
     type ValueType = i32;
     fn auto_increment() -> bool {
         true

tests/common/features/dyn_table_name_lazy_static.rs

@@ -32,6 +32,8 @@ pub enum PrimaryKey {
 }
 
 impl PrimaryKeyTrait for PrimaryKey {
+    const ARITY: usize = 1;
+
     type ValueType = i32;
 
     fn auto_increment() -> bool {