Refactor code structure for improved readability and maintainability

src/app/app.module.ts

@@ -0,0 +1,31 @@
+import { Module } from "@nestjs/common";
+import { TypeOrmModule } from "@nestjs/typeorm";
+import { ConfigModule } from "@nestjs/config";
+import { User } from "../entities/user.entity";
+import { UserService } from "../services/user.service";
+
+@Module({
+  imports: [
+    ConfigModule.forRoot({
+      isGlobal: true,
+      envFilePath: ".env",
+    }),
+    TypeOrmModule.forRoot({
+      type: "mariadb",
+      host: process.env.DB_HOST || "localhost",
+      port: parseInt(process.env.DB_PORT) || 3306,
+      username: process.env.DB_USERNAME || "root",
+      password: process.env.DB_PASSWORD || "",
+      database: process.env.DB_DATABASE || "low_code_engine",
+      entities: [__dirname + "/../**/*.entity{.ts,.js}"],
+      migrations: [__dirname + "/../migrations/*{.ts,.js}"],
+      synchronize: process.env.NODE_ENV === "development",
+      migrationsRun: process.env.NODE_ENV === "production",
+      autoLoadEntities: true,
+    }),
+    TypeOrmModule.forFeature([User]),
+  ],
+  controllers: [],
+  providers: [UserService],
+})
+export class AppModule {}

src/data-source.ts

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+import { DataSource } from "typeorm";
+import { config } from "dotenv";
+
+// Load environment variables
+config();
+
+export default new DataSource({
+  type: "mariadb",
+  host: process.env.DB_HOST || "localhost",
+  port: parseInt(process.env.DB_PORT) || 3306,
+  username: process.env.DB_USERNAME || "root",
+  password: process.env.DB_PASSWORD || "",
+  database: process.env.DB_DATABASE || "low_code_engine",
+  entities: ["src/**/*.entity{.ts,.js}"],
+  migrations: ["src/migrations/*{.ts,.js}"],
+  synchronize: false,
+  logging: false,
+});

src/entities/user.entity.ts

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+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+} from "typeorm";
+
+@Entity("users")
+export class User {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ unique: true })
+  email: string;
+
+  @Column()
+  firstName: string;
+
+  @Column()
+  lastName: string;
+
+  @Column({ default: true })
+  isActive: boolean;
+
+  @CreateDateColumn()
+  createdAt: Date;
+
+  @UpdateDateColumn()
+  updatedAt: Date;
+}

src/main.ts

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+import { NestFactory } from "@nestjs/core";
+import { AppModule } from "./app/app.module";
+
+async function bootstrap() {
+  const app = await NestFactory.create(AppModule);
+  await app.listen(3000);
+}
+
+bootstrap();

src/migrations/1757413588655-Init.ts

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+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class Init1757413588655 implements MigrationInterface {
+    name = 'Init1757413588655'
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`CREATE TABLE \`users\` (\`id\` int NOT NULL AUTO_INCREMENT, \`email\` varchar(255) NOT NULL, \`firstName\` varchar(255) NOT NULL, \`lastName\` varchar(255) NOT NULL, \`isActive\` tinyint NOT NULL DEFAULT 1, \`createdAt\` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6), \`updatedAt\` datetime(6) NOT NULL DEFAULT CURRENT_TIMESTAMP(6) ON UPDATE CURRENT_TIMESTAMP(6), UNIQUE INDEX \`IDX_97672ac88f789774dd47f7c8be\` (\`email\`), PRIMARY KEY (\`id\`)) ENGINE=InnoDB`);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`DROP INDEX \`IDX_97672ac88f789774dd47f7c8be\` ON \`users\``);
+        await queryRunner.query(`DROP TABLE \`users\``);
+    }
+
+}

src/services/user.service.ts

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+import { Injectable } from "@nestjs/common";
+import { InjectRepository } from "@nestjs/typeorm";
+import { Repository } from "typeorm";
+import { User } from "../entities/user.entity";
+
+@Injectable()
+export class UserService {
+  constructor(
+    @InjectRepository(User)
+    private userRepository: Repository<User>
+  ) {}
+
+  async findAll(): Promise<User[]> {
+    return this.userRepository.find();
+  }
+
+  async findOne(id: number): Promise<User> {
+    return this.userRepository.findOne({ where: { id } });
+  }
+
+  async create(userData: Partial<User>): Promise<User> {
+    const user = this.userRepository.create(userData);
+    return this.userRepository.save(user);
+  }
+
+  async update(id: number, userData: Partial<User>): Promise<User> {
+    await this.userRepository.update(id, userData);
+    return this.findOne(id);
+  }
+
+  async remove(id: number): Promise<void> {
+    await this.userRepository.delete(id);
+  }
+}