fix: get correct insert ids for multiple entities inserted

src/driver/Driver.ts

@@ -175,7 +175,7 @@ export interface Driver {
     /**
      * Creates generated map of values generated or returned by database after INSERT query.
      */
-    createGeneratedMap(metadata: EntityMetadata, insertResult: any): ObjectLiteral|undefined;
+    createGeneratedMap(metadata: EntityMetadata, insertResult: any, entityIndex?: number, entityNum?: number): ObjectLiteral|undefined;
 
     /**
      * Differentiate columns of this table and columns from the given column metadatas columns

src/driver/mysql/MysqlDriver.ts

@@ -709,11 +709,13 @@ export class MysqlDriver implements Driver {
     /**
      * Creates generated map of values generated or returned by database after INSERT query.
      */
-    createGeneratedMap(metadata: EntityMetadata, insertResult: any) {
+    createGeneratedMap(metadata: EntityMetadata, insertResult: any, entityIndex: number) {
         const generatedMap = metadata.generatedColumns.reduce((map, generatedColumn) => {
             let value: any;
             if (generatedColumn.generationStrategy === "increment" && insertResult.insertId) {
-                value = insertResult.insertId;
+                // NOTE: When multiple rows is inserted by a single INSERT statement,
+                // `insertId` is the value generated for the first inserted row only.
+                value = insertResult.insertId + entityIndex;
             // } else if (generatedColumn.generationStrategy === "uuid") {
             //     console.log("getting db value:", generatedColumn.databaseName);
             //     value = generatedColumn.getEntityValue(uuidMap);

src/driver/sqlite-abstract/AbstractSqliteDriver.ts

@@ -507,11 +507,13 @@ export abstract class AbstractSqliteDriver implements Driver {
     /**
      * Creates generated map of values generated or returned by database after INSERT query.
      */
-    createGeneratedMap(metadata: EntityMetadata, insertResult: any) {
+    createGeneratedMap(metadata: EntityMetadata, insertResult: any, entityIndex: number, entityNum: number) {
         const generatedMap = metadata.generatedColumns.reduce((map, generatedColumn) => {
             let value: any;
             if (generatedColumn.generationStrategy === "increment" && insertResult) {
-                value = insertResult;
+                // NOTE: When INSERT statement is successfully completed, the last inserted row ID is returned.
+                // see also: SqliteQueryRunner.query()
+                value = insertResult - entityNum + entityIndex + 1;
             // } else if (generatedColumn.generationStrategy === "uuid") {
             //     value = insertValue[generatedColumn.databaseName];
             }

src/query-builder/ReturningResultsEntityUpdator.ts

@@ -93,7 +93,7 @@ export class ReturningResultsEntityUpdator {
             }
             // get all values generated by a database for us
             const result = Array.isArray(insertResult.raw) ? insertResult.raw[entityIndex] : insertResult.raw;
-            const generatedMap = this.queryRunner.connection.driver.createGeneratedMap(metadata, result) || {};
+            const generatedMap = this.queryRunner.connection.driver.createGeneratedMap(metadata, result, entityIndex, entities.length) || {};
 
             // if database does not support uuid generation we need to get uuid values
             // generated by orm and set them to the generatedMap

test/github-issues/2131/entity/Post.ts

@@ -0,0 +1,12 @@
+import { PrimaryGeneratedColumn, Entity, Column } from "../../../../src";
+
+@Entity()
+export class Post {
+
+    @PrimaryGeneratedColumn()
+    id: number | null;
+
+    @Column()
+    title: string;
+
+}

test/github-issues/2131/issue-2131.ts

@@ -0,0 +1,53 @@
+import "reflect-metadata";
+import {
+    closeTestingConnections,
+    createTestingConnections,
+    reloadTestingDatabases,
+} from "../../utils/test-utils";
+import { Connection } from "../../../src/connection/Connection";
+import { expect } from "chai";
+import { Post } from "./entity/Post";
+
+describe("github issues > #2131 InsertResult return the same primary key", () => {
+    let connections: Connection[];
+    const posts: Post[] = [{
+        id: null,
+        title: "Post 1",
+    }, {
+        id: null,
+        title: "Post 2",
+    }, {
+        id: null,
+        title: "Post 3",
+    }, {
+        id: null,
+        title: "Post 4",
+    }];
+
+    before(
+        async () =>
+            (connections = await createTestingConnections({
+                entities: [__dirname + "/entity/*{.js,.ts}"],
+                enabledDrivers: ["sqlite", "mysql"],
+            }))
+    );
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should get correct insert ids for multiple entities inserted", () =>
+        Promise.all(
+            connections.map(async (connection) => {
+                await connection
+                    .createQueryBuilder()
+                    .insert()
+                    .into(Post)
+                    .values(posts)
+                    .execute();
+
+                expect(posts[0].id).to.equal(1);
+                expect(posts[1].id).to.equal(2);
+                expect(posts[2].id).to.equal(3);
+                expect(posts[3].id).to.equal(4);
+            })
+        ));
+});