start relations (has one or many; has one; has many)

orm/src/builder/type/ConnectionExecutable.ts

@@ -6,7 +6,7 @@ import {Connection} from '../../db/Connection.ts'
 import {ResultCollection} from './result/ResultCollection.ts'
 import {ResultIterable} from './result/ResultIterable.ts'
 import ResultOperator from './result/ResultOperator.ts'
-import {Collection} from '../../../../lib/src/collection/Collection.ts'
+import {collect, Collection} from '../../../../lib/src/collection/Collection.ts'
 import NoTargetOperatorError from '../../error/NoTargetOperatorError.ts'
 
 export default abstract class ConnectionExecutable<T> {
@@ -21,12 +21,17 @@ export default abstract class ConnectionExecutable<T> {
             throw new Error('Unable to execute database item: no target connection.')
         }
 
-        if ( !this.__target_operator ) throw new NoTargetOperatorError()
-
         const query = `SELECT * FROM (${this.sql(0)}) AS target_query OFFSET ${i} LIMIT 1`
         const result = await this.__target_connection.query(query)
         const row = result.rows.first()
-        if ( row ) return this.__target_operator.inflate_row(row)
+        if ( row ) {
+            if ( !this.__target_operator ) throw new NoTargetOperatorError()
+
+            const inflated = this.__target_operator.inflate_row(row)
+            await this.__target_operator.process_eager_loads(this, collect([inflated]))
+
+            return inflated
+        }
     }
 
     async get_range(start: number, end: number): Promise<Collection<T>> {
@@ -36,10 +41,15 @@ export default abstract class ConnectionExecutable<T> {
 
         const query = `SELECT * FROM (${this.sql(0)}) AS target_query OFFSET ${start} LIMIT ${(end - start) + 1}`
         const result = await this.__target_connection.query(query)
-        return result.rows.map(row => {
+        const inflated = result.rows.map(row => {
             if ( !this.__target_operator ) throw new NoTargetOperatorError()
             return this.__target_operator.inflate_row(row)
         })
+
+        if ( !this.__target_operator ) throw new NoTargetOperatorError()
+        await this.__target_operator.process_eager_loads(this, inflated)
+
+        return inflated
     }
 
     iterator(): ResultIterable<T> {

orm/src/builder/type/Select.ts

@@ -20,6 +20,7 @@ import {FullOuterJoin} from './join/FullOuterJoin.ts'
 import {HavingBuilder} from './HavingBuilder.ts'
 import ConnectionExecutable from './ConnectionExecutable.ts'
 import {Scope} from '../Scope.ts'
+import {isInstantiable} from "../../../../di/src/type/Instantiable.ts";
 
 export type WhereBuilderFunction = (group: WhereBuilder) => any
 export type HavingBuilderFunction = (group: HavingBuilder) => any
@@ -78,6 +79,37 @@ export class Select<T> extends ConnectionExecutable<T> {
         return this
     }
 
+    clear_fields() {
+        this._fields = []
+        return this
+    }
+
+    clone(): Select<T> {
+        const constructor = this.constructor as typeof Select
+        if ( !isInstantiable<Select<T>>(constructor) ) {
+            throw new TypeError(`Parent constructor is not instantiable.`)
+        }
+
+        const select = new constructor()
+
+        select._fields = this._fields
+        select._source = this._source
+        select._wheres = this._wheres
+        select._scopes = this._scopes
+        select._havings = this._havings
+        select._limit = this._limit
+        select._offset = this._offset
+        select._joins = this._joins
+        select._distinct = this._distinct
+        select._group_by = this._group_by
+        select._order = this._order
+
+        select.__target_connection = this.__target_connection
+        select.__target_operator = this.__target_operator
+
+        return select
+    }
+
     group_by(...groupings: string[]) {
         this._group_by = groupings
         return this

orm/src/builder/type/result/ResultOperator.ts

@@ -1,8 +1,11 @@
 import {QueryRow} from '../../../db/types.ts'
+import ConnectionExecutable from '../ConnectionExecutable.ts'
+import {Model} from '../../../model/Model.ts'
+import {Collection} from '../../../../../lib/src/collection/Collection.ts'
 
 export default abstract class ResultOperator<T> {
+    public async process_eager_loads<T2>(query: ConnectionExecutable<T2>, results: Collection<T>): Promise<void> { }
 
     abstract inflate_row(row: QueryRow): T
     abstract deflate_row(item: T): QueryRow
-
 }

orm/src/model/Model.ts

@@ -11,10 +11,12 @@ import {logger} from '../../../lib/src/service/logging/global.ts'
 import {QueryFilter} from './filter.ts'
 import {BehaviorSubject} from '../../../lib/src/support/BehaviorSubject.ts'
 import {Scope} from '../builder/Scope.ts'
-import {JSONState, Rehydratable} from '../../../lib/src/support/Rehydratable.ts'
+import {Rehydratable} from '../../../lib/src/support/Rehydratable.ts'
 import {HasOne} from './relation/HasOne.ts'
 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";
 
 // TODO separate read/write connections
 // TODO manual dirty flags
@@ -246,9 +248,13 @@ abstract class Model<T extends Model<T>> extends Builder<T> implements Rehydrata
      * @param {...FieldSet} fields
      */
     public select(...fields: FieldSet[]) {
+        if ( fields.length < 1 ) fields.push(this.qualify_column('*'))
+
         const constructor = (this.constructor as typeof Model)
-        return super.select(...fields)
-            .from(constructor.table_name())
+        const select = new ModelSelect<T>()
+
+        return select.fields(...fields)
+            .from(constructor.query_source())
             .with_scopes(constructor.global_scopes)
             .target_connection(constructor.get_connection())
             .target_operator(make(ModelResultOperator, constructor))
@@ -972,6 +978,17 @@ abstract class Model<T extends Model<T>> extends Builder<T> implements Rehydrata
     public has_many<T>(related: Instantiable<T>, foreign_key?: string, local_key?: string) {
         return new HasMany(this as any, new related() as any, foreign_key, local_key)
     }
+
+    public get_relation<T2 extends Model<T2>>(name: string): Relation<T, T2> {
+        // @ts-ignore
+        const rel: any = this[name]()
+
+        if ( rel instanceof Relation ) {
+            return rel
+        }
+
+        throw new TypeError(`Cannot get relation of name: ${name}. Method does not return relation.`)
+    }
 }
 
 export { Model }

orm/src/model/ModelResultOperator.ts

@@ -4,6 +4,9 @@ import {Injectable} from '../../../di/src/decorator/Injection.ts'
 import {QueryRow} from '../db/types.ts'
 import Instantiable from '../../../di/src/type/Instantiable.ts'
 import {make} from '../../../di/src/global.ts'
+import ConnectionExecutable from '../builder/type/ConnectionExecutable.ts'
+import {Collection} from '../../../lib/src/collection/Collection.ts'
+import {ModelSelect} from './query/ModelSelect.ts'
 
 @Injectable()
 export default class ModelResultOperator<T extends Model<T>> extends ResultOperator<T> {
@@ -21,4 +24,21 @@ export default class ModelResultOperator<T extends Model<T>> extends ResultOpera
         return item.to_row()
     }
 
+    public async process_eager_loads<T2>(query: ConnectionExecutable<T2>, results: Collection<T>) {
+        if ( query instanceof ModelSelect ) {
+            const eagers = query.eager_relations
+            const model = new this.ModelClass()
+
+            for ( const rel_name of eagers ) {
+                const relation = model.get_relation(rel_name)
+                const select = await relation.build_eager_query(query, results)
+                const all_related = await select.results()
+                results.each(result => {
+                    const result_relation = result.get_relation(rel_name)
+                    const result_related = result_relation.match_results(all_related as any)
+                    result_relation.set_value(result_related as any)
+                })
+            }
+        }
+    }
 }

orm/src/model/query/ModelSelect.ts

@@ -0,0 +1,20 @@
+import {Select} from '../../builder/type/Select.ts'
+
+export class ModelSelect<T> extends Select<T> {
+    protected _withs: string[] = []
+
+    public with(related: string) {
+        this._withs.push(related)
+        return this
+    }
+
+    public get eager_relations(): string[] {
+        return [...this._withs]
+    }
+
+    clone(): ModelSelect<T> {
+        const select = super.clone() as ModelSelect<T>
+        select._withs = this._withs
+        return select
+    }
+}

orm/src/model/relation/HasMany.ts

@@ -3,7 +3,23 @@ import {HasOneOrMany} from './HasOneOrMany.ts'
 import {Collection} from '../../../../lib/src/collection/Collection.ts'
 
 export class HasMany<T extends Model<T>, T2 extends Model<T2>> extends HasOneOrMany<T, T2> {
+    protected _value?: Collection<T2>
+    protected _loaded = false
+
     public async get(): Promise<Collection<T2>> {
         return this.fetch().collect()
     }
+
+    public set_value(related: Collection<T2>) {
+        this._loaded = true
+        this._value = related.clone()
+    }
+
+    public get_value(): Collection<T2> | undefined {
+        return this._value
+    }
+
+    public is_loaded(): boolean {
+        return this._loaded
+    }
 }

orm/src/model/relation/HasOne.ts

@@ -1,8 +1,30 @@
 import {Model} from '../Model.ts'
 import {HasOneOrMany} from './HasOneOrMany.ts'
+import {Collection} from "../../../../lib/src/collection/Collection.ts";
+import {Logging} from "../../../../lib/src/service/logging/Logging.ts";
 
 export class HasOne<T extends Model<T>, T2 extends Model<T2>> extends HasOneOrMany<T, T2> {
+    protected _value?: T2
+    protected _loaded = false
+
     public async get(): Promise<T2 | undefined> {
         return this.fetch().first()
     }
+
+    public set_value(related: Collection<T2>) {
+        this._value = related.first()
+        this._loaded = true
+
+        if ( related.length > 1 ) {
+            this.make(Logging).warn(`HasOne relation result contained more than one value for ${this.qualified_local_key} -> ${this.qualified_local_key}`)
+        }
+    }
+
+    public get_value(): T2 | undefined {
+        return this._value
+    }
+
+    public is_loaded(): boolean {
+        return this._loaded
+    }
 }

orm/src/model/relation/HasOneOrMany.ts

@@ -1,7 +1,9 @@
-import {Model} from "../Model.ts";
-import {Relation} from "./Relation.ts";
-import ConnectionExecutable from "../../builder/type/ConnectionExecutable.ts";
-import {WhereBuilder} from "../../builder/type/WhereBuilder.ts";
+import {Model} from '../Model.ts'
+import {Relation} from './Relation.ts'
+import ConnectionExecutable from '../../builder/type/ConnectionExecutable.ts'
+import {WhereBuilder} from '../../builder/type/WhereBuilder.ts'
+import {ModelSelect} from '../query/ModelSelect.ts'
+import {Collection} from '../../../../lib/src/collection/Collection.ts'
 
 export abstract class HasOneOrMany<T extends Model<T>, T2 extends Model<T2>> extends Relation<T, T2> {
     constructor(
@@ -42,4 +44,13 @@ export abstract class HasOneOrMany<T extends Model<T>, T2 extends Model<T2>> ext
                 .whereRaw(this.qualified_foreign_key, 'IS NOT', 'NULL')
         })
     }
+
+    public build_eager_query(parent_query: ModelSelect<T>, result: Collection<T>): ModelSelect<T2> {
+        const keys = result.pluck(this.local_key).toArray()
+        return this.related.select().whereIn(this.foreign_key, keys)
+    }
+
+    public match_results(possibly_related: Collection<T>) {
+        return possibly_related.where(this.foreign_key, '=', this.parent_value)
+    }
 }

orm/src/model/relation/Relation.ts

@@ -6,10 +6,12 @@ import {AsyncCollection} from '../../../../lib/src/collection/AsyncCollection.ts
 import {Collection} from '../../../../lib/src/collection/Collection.ts'
 import {WhereBuilder} from '../../builder/type/WhereBuilder.ts'
 import {RelationBuilder} from './RelationBuilder.ts'
-import {Select} from "../../builder/type/Select.ts";
-import {FieldSet} from "../../builder/types.ts";
-import {Update} from "../../builder/type/Update.ts";
-import {Delete} from "../../builder/type/Delete.ts";
+import {Select} from '../../builder/type/Select.ts'
+import {FieldSet} from '../../builder/types.ts'
+import {Update} from '../../builder/type/Update.ts'
+import {Delete} from '../../builder/type/Delete.ts'
+import ModelResultOperator from '../ModelResultOperator.ts'
+import {ModelSelect} from '../query/ModelSelect.ts'
 
 export type RelationResult<T> = T | Collection<T> | undefined
 
@@ -25,13 +27,21 @@ export abstract class Relation<T extends Model<T>, T2 extends Model<T2>> extends
 
     public get_operator() {
         const related_class = this.related.constructor as typeof Model
-        return this.make(RelationResultOperator, related_class, this)
+        return this.make(ModelResultOperator, related_class)
     }
 
     public abstract query(): ConnectionExecutable<T2>
 
     public abstract scope_query(where: WhereBuilder): void
 
+    public abstract build_eager_query(parent_query: ModelSelect<T>, result: Collection<T>): ModelSelect<T2>
+
+    public abstract match_results(possibly_related: Collection<T>): Collection<T>
+
+    public abstract set_value(related: Collection<T2>): void
+    public abstract get_value(): Collection<T2> | T2 | undefined
+    public abstract is_loaded(): boolean
+
     public fetch(): AsyncCollection<T2> {
         return this.query().results()
     }
@@ -39,7 +49,21 @@ export abstract class Relation<T extends Model<T>, T2 extends Model<T2>> extends
     public abstract get(): Promise<RelationResult<T2>>
 
     public then(callback: (result: RelationResult<T2>) => any) {
-        this.get().then(callback)
+        if ( this.is_loaded() ) {
+            callback(this.get_value() as RelationResult<T2>)
+        } else {
+            this.get().then(result => {
+                if ( result instanceof Collection ) {
+                    this.set_value(result as any)
+                }
+
+                callback(result)
+            })
+        }
+    }
+
+    public get value(): RelationResult<T2> {
+        return this.get_value()
     }
 
     public get related_query_source() {