feat: add transformer to ViewColumnOptions

docs/view-entities.md

@@ -2,6 +2,7 @@
 
 * [What is View Entity?](#what-is-view-entity)
 * [View Entity columns](#view-entity-columns)
+* [View Column options](#view-column-options)
 * [Complete example](#complete-example)
 
 ## What is View Entity?
@@ -148,6 +149,26 @@ export class PostCategory {
 }
 ```
 
+## View Column options
+
+View Column options define additional options for your view entity columns, similar to [column options](entities.md#column-options) for regular entities.
+
+You can specify view column options in `@ViewColumn`:
+
+```typescript
+@ViewColumn({
+    name: "postName",
+    // ...
+})
+name: string;
+```
+
+List of available options in `ViewColumnOptions`:
+
+* `name: string` - Column name in the database view.
+* `transformer: { from(value: DatabaseType): EntityType, to(value: EntityType): DatabaseType }` - Used to unmarshal properties of arbitrary type `DatabaseType` supported by the database into a type `EntityType`. Arrays of transformers are also supported and are applied in reverse order when reading. Note that because database views are read-only, `transformer.to(value)` will never be used.
+
+
 ## Complete example
 
 Let create two entities and a view containing aggregated data from these entities:

src/decorator/options/ViewColumnOptions.ts

@@ -1,3 +1,5 @@
+import { ValueTransformer } from "./ValueTransformer";
+
 /**
  * Describes all view column's options.
  */
@@ -6,4 +8,10 @@ export interface ViewColumnOptions {
      * Column name in the database.
      */
     name?: string;
+
+    /**
+     * Specifies a value transformer(s) that is to be used to unmarshal
+     * this column when reading from the database.
+     */
+     transformer?: ValueTransformer|ValueTransformer[];
 }

test/functional/view-entity/general/entity/PhotoAlbum.ts

@@ -0,0 +1,43 @@
+import {Connection, ValueTransformer} from "../../../../../src";
+import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
+import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
+import {Album} from "./Album";
+import {Photo} from "./Photo";
+
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
+
+export const lowercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleLowerCase()
+}
+
+export const removeWhitespace: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.replace(/\s/g, '')
+}
+@ViewEntity({
+    expression: (connection: Connection) => connection.createQueryBuilder()
+        .select("photo.id", "id")
+        .addSelect("photo.name", "name")
+        .addSelect("photo.albumId", "albumId")
+        .addSelect("album.name", "albumName")
+        .from(Photo, "photo")
+        .leftJoin(Album, "album", "album.id = photo.albumId")
+        .where("album.name = 'Boeing photos'")
+})
+export class PhotoAlbum {
+    @ViewColumn()
+    id: number;
+
+    @ViewColumn({transformer: [lowercase, removeWhitespace]})
+    name: string;
+
+    @ViewColumn({transformer: uppercase})
+    albumName: string;
+
+    @ViewColumn({ name: "albumId" })
+    photoAlbumId: number;
+}

test/functional/view-entity/general/view-entity-general.ts

@@ -9,6 +9,7 @@ import {Photo} from "./entity/Photo";
 import {PhotoAlbumCategory} from "./entity/PhotoAlbumCategory";
 import {Post} from "./entity/Post";
 import {PostCategory} from "./entity/PostCategory";
+import { PhotoAlbum } from "./entity/PhotoAlbum";
 
 describe("view entity > general", () => {
 
@@ -112,5 +113,10 @@ describe("view entity > general", () => {
         photoAlbumCategory!.categoryName.should.be.equal("Cars");
         photoAlbumCategory!.photoAlbumId.should.be.equal(albumId);
 
+        const photoAlbums = await connection.manager.find(PhotoAlbum);
+        const photoId3 = connection.driver instanceof CockroachDriver ? "3" : 3;
+        photoAlbums[0].id.should.be.equal(photoId3);
+        photoAlbums[0].name.should.be.equal('boeing737')
+        photoAlbums[0].albumName.should.be.equal('BOEING PHOTOS')
     })));
 });

test/functional/view-entity/mssql/entity/PostCategory.ts

@@ -1,6 +1,12 @@
+import { ValueTransformer } from "../../../../../src";
 import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
 import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
 
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
+
 @ViewEntity({ expression: `
     SELECT "post"."id" "id", "post"."name" AS "name", "category"."name" AS "categoryName"
     FROM "post" "post"
@@ -14,7 +20,7 @@ export class PostCategory {
     @ViewColumn({ name: "name" })
     postName: string;
 
-    @ViewColumn()
+    @ViewColumn({ transformer: uppercase})
     categoryName: string;
 
 }

test/functional/view-entity/mssql/view-entity-mssql.ts

@@ -50,11 +50,11 @@ describe("view entity > mssql", () => {
 
         postCategories[0].id.should.be.equal(1);
         postCategories[0].postName.should.be.equal("About BMW");
-        postCategories[0].categoryName.should.be.equal("Cars");
+        postCategories[0].categoryName.should.be.equal("CARS");
 
         postCategories[1].id.should.be.equal(2);
         postCategories[1].postName.should.be.equal("About Boeing");
-        postCategories[1].categoryName.should.be.equal("Airplanes");
+        postCategories[1].categoryName.should.be.equal("AIRPLANES");
 
     })));
 });

test/functional/view-entity/mysql/entity/PostCategory.ts

@@ -1,6 +1,13 @@
+
+import { ValueTransformer } from "../../../../../src";
 import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
 import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
 
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
+
 @ViewEntity({ expression: `
     SELECT \`post\`.\`id\` \`id\`, \`post\`.\`name\` AS \`name\`, \`category\`.\`name\` AS \`categoryName\`
     FROM \`post\` \`post\`
@@ -14,7 +21,7 @@ export class PostCategory {
     @ViewColumn({ name: "name" })
     postName: string;
 
-    @ViewColumn()
+    @ViewColumn({transformer: uppercase})
     categoryName: string;
 
 }

test/functional/view-entity/mysql/view-entity-mysql.ts

@@ -50,11 +50,11 @@ describe("view entity > mysql", () => {
 
         postCategories[0].id.should.be.equal(1);
         postCategories[0].postName.should.be.equal("About BMW");
-        postCategories[0].categoryName.should.be.equal("Cars");
+        postCategories[0].categoryName.should.be.equal("CARS");
 
         postCategories[1].id.should.be.equal(2);
         postCategories[1].postName.should.be.equal("About Boeing");
-        postCategories[1].categoryName.should.be.equal("Airplanes");
+        postCategories[1].categoryName.should.be.equal("AIRPLANES");
 
     })));
 });

test/functional/view-entity/oracle/entity/PostCategory.ts

@@ -1,6 +1,11 @@
+import { ValueTransformer } from "../../../../../src";
 import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
 import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
 
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
 @ViewEntity({ expression: `
     SELECT "post"."id" "id", "post"."name" AS "name", "category"."name" AS "categoryName"
     FROM "post" "post"
@@ -14,7 +19,7 @@ export class PostCategory {
     @ViewColumn({ name: "name" })
     postName: string;
 
-    @ViewColumn()
+    @ViewColumn({transformer: uppercase})
     categoryName: string;
 
 }

test/functional/view-entity/oracle/view-entity-oracle.ts

@@ -50,11 +50,11 @@ describe("view entity > oracle", () => {
 
         postCategories[0].id.should.be.equal(1);
         postCategories[0].postName.should.be.equal("About BMW");
-        postCategories[0].categoryName.should.be.equal("Cars");
+        postCategories[0].categoryName.should.be.equal("CARS");
 
         postCategories[1].id.should.be.equal(2);
         postCategories[1].postName.should.be.equal("About Boeing");
-        postCategories[1].categoryName.should.be.equal("Airplanes");
+        postCategories[1].categoryName.should.be.equal("AIRPLANES");
 
     })));
 });

test/functional/view-entity/postgres/entity/PostCategory.ts

@@ -1,6 +1,11 @@
+import { ValueTransformer } from "../../../../../src";
 import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
 import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
 
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
 @ViewEntity({ expression: `
     SELECT "post"."id" "id", "post"."name" AS "name", "category"."name" AS "categoryName"
     FROM "post" "post"
@@ -14,7 +19,7 @@ export class PostCategory {
     @ViewColumn({ name: "name" })
     postName: string;
 
-    @ViewColumn()
+    @ViewColumn({transformer: uppercase})
     categoryName: string;
 
 }

test/functional/view-entity/postgres/view-entity-postgres.ts

@@ -76,11 +76,11 @@ describe("view entity > postgres", () => {
 
         postCategories[0].id.should.be.equal(1);
         postCategories[0].postName.should.be.equal("About BMW");
-        postCategories[0].categoryName.should.be.equal("Cars");
+        postCategories[0].categoryName.should.be.equal("CARS");
 
         postCategories[1].id.should.be.equal(2);
         postCategories[1].postName.should.be.equal("About Boeing");
-        postCategories[1].categoryName.should.be.equal("Airplanes");
+        postCategories[1].categoryName.should.be.equal("AIRPLANES");
 
     })));
 });

test/functional/view-entity/sqlite/entity/PostCategory.ts

@@ -1,6 +1,12 @@
+import { ValueTransformer } from "../../../../../src";
 import {ViewColumn} from "../../../../../src/decorator/columns/ViewColumn";
 import {ViewEntity} from "../../../../../src/decorator/entity-view/ViewEntity";
 
+export const uppercase: ValueTransformer = {
+    to: (entityValue: string) => {},
+    from: (databaseValue: string) => databaseValue.toLocaleUpperCase()
+};
+
 @ViewEntity({ expression: `
     SELECT "post"."id" "id", "post"."name" AS "name", "category"."name" AS "categoryName"
     FROM "post" "post"
@@ -14,7 +20,7 @@ export class PostCategory {
     @ViewColumn({ name: "name" })
     postName: string;
 
-    @ViewColumn()
+    @ViewColumn({transformer: uppercase})
     categoryName: string;
 
 }

test/functional/view-entity/sqlite/view-entity-sqlite.ts

@@ -50,11 +50,11 @@ describe("view entity > sqlite", () => {
 
         postCategories[0].id.should.be.equal(1);
         postCategories[0].postName.should.be.equal("About BMW");
-        postCategories[0].categoryName.should.be.equal("Cars");
+        postCategories[0].categoryName.should.be.equal("CARS");
 
         postCategories[1].id.should.be.equal(2);
         postCategories[1].postName.should.be.equal("About Boeing");
-        postCategories[1].categoryName.should.be.equal("Airplanes");
+        postCategories[1].categoryName.should.be.equal("AIRPLANES");
 
     })));
 });