Create belongs_to_one and belongs_to_many inverse helpers

app/index.ts

@@ -29,6 +29,10 @@ console.log(sel.clone())
 const gm = await sel.results().first()
 
 console.log(gm)
-console.log(await gm.login_attempts())
+
+const la = (await gm.login_attempts()).first()
+console.log(la)
+
+console.log(await la.user())
 
 // console.log(await las.fetchRelated())

app/models/LoginAttempt.model.ts

@@ -1,6 +1,8 @@
 import {Model} from '../../orm/src/model/Model.ts'
 import {Field} from '../../orm/src/model/Field.ts'
 import {Type} from '../../orm/src/db/types.ts'
+import UserModel from "./User.model.ts";
+import {Relation} from "../../orm/src/model/relation/decorators.ts";
 
 export default class LoginAttemptModel extends Model<LoginAttemptModel> {
     protected static table = 'daton_login_attempts'
@@ -17,4 +19,9 @@ export default class LoginAttemptModel extends Model<LoginAttemptModel> {
 
     @Field(Type.timestamp)
     protected attempt_date!: Date
+
+    @Relation()
+    public user() {
+        return this.belongs_to_one(UserModel, 'login_attempts')
+    }
 }

orm/src/model/Model.ts

@@ -17,6 +17,7 @@ import Instantiable from '../../../di/src/type/Instantiable.ts'
 import {HasMany} from './relation/HasMany.ts'
 import {ModelSelect} from "./query/ModelSelect.ts";
 import {Relation} from "./relation/Relation.ts";
+import {HasOneOrMany} from "./relation/HasOneOrMany.ts";
 
 // TODO separate read/write connections
 // TODO manual dirty flags
@@ -979,6 +980,38 @@ abstract class Model<T extends Model<T>> extends Builder<T> implements Rehydrata
         return new HasMany(this as any, new related() as any, foreign_key, local_key)
     }
 
+    /**
+     * Defines the inverse of a has one or many relation.
+     * @param {typeof Model} related
+     * @param {string} relation_name - the name of the relation function on the inverse
+     */
+    public belongs_to_one<T extends Model<T>>(related: Instantiable<T>, relation_name: string) {
+        const related_inst = new related()
+        const relation = related_inst.get_relation(relation_name)
+
+        if ( !(relation instanceof HasOneOrMany) ) {
+            throw new TypeError(`Cannot create belongs to one relation. Inverse relation must be has one or many.`)
+        }
+
+        return new HasOne(this as any, related_inst, relation.local_key, relation.foreign_key)
+    }
+
+    /**
+     * Defines the inverse of a has one or many relation.
+     * @param {typeof Model} related
+     * @param {string} relation_name - the name of the relation function on the inverse
+     */
+    public belongs_to_many<T extends Model<T>>(related: Instantiable<T>, relation_name: string) {
+        const related_inst = new related()
+        const relation = related_inst.get_relation(relation_name)
+
+        if ( !(relation instanceof HasOneOrMany) ) {
+            throw new TypeError(`Cannot create belongs to one relation. Inverse relation must be has one or many.`)
+        }
+
+        return new HasMany(this as any, related_inst, relation.local_key, relation.foreign_key)
+    }
+
     public get_relation<T2 extends Model<T2>>(name: string): Relation<T, T2> {
         // @ts-ignore
         const rel: any = this[name]()