Connect to OceanBase Database in MySQL mode by using TypeORM

node -v
npm -v

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "target": "es6",
    "module": "commonjs",
    "outDir": "./dist",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": ["src/**/*.ts"],
  "exclude": ["node_modules"]
}

import { Entity, PrimaryGeneratedColumn, Column } from "typeorm";

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id?: number;

  @Column()
  firstName: string = "";

  @Column()
  lastName: string = "";

  @Column({ unique: true })
  email: string = "";

  @Column()
  age: number = 0;
}

import 'reflect-metadata';
import { createConnection } from 'typeorm';
import { User } from './entity/User';

async function main() {
  // 1. Create a database connection
  const connection = await createConnection();
  console.log('Database connection established');

  // 2. Create a new user
  const user = new User();
  user.firstName = "Zhang";
  user.lastName = "San";
  user.email = "zhangsan@example.com";
  user.age = 25;

  await connection.manager.save(user);
  console.log('User saved, User ID: ', user.id);

  // 3. Query all users
  const users = await connection.manager.find(User);
  console.log('All users: ', users);

  // 4. Query by conditions
  const specificUser = await connection.manager.findOne(User, {
    where: {
      firstName: "Zhang",
      lastName: "San"
    }
  });
  console.log('Query by conditions: ', specificUser);

  // 5. Use QueryBuilder for complex queries
  const userRepository = connection.getRepository(User);
  const queryBuilderUsers = await userRepository
    .createQueryBuilder("user")
    .where("user.age > :age", { age: 18 })
    .orderBy("user.age", "DESC")
    .getMany();
  console.log('Complex query: ', queryBuilderUsers);

  // 6. Update records
  await connection
    .createQueryBuilder()
    .update(User)
    .set({ firstName: "Li", lastName: "Si" })
    .where("id = :id", { id: 1 })
    .execute();
  const updateUsers = await connection.manager.find(User);
  console.log('Updated records: ', updateUsers);

  // 7. Delete records
  await connection
    .createQueryBuilder()
    .delete()
    .from(User)
    .where("id = :id", { id: 1 })
    .execute();
  const deleteUsers = await connection.manager.find(User);
  console.log('Deleted records: ', deleteUsers);
}

main().catch(error => {
  console.error('Error occurred:', error);
  process.exit(1);
});