egg-mysql

Aliyun rds client(support mysql portocal) for egg framework

Install

npm i egg-mysql --save

MySQL Plugin for egg, support egg application access to MySQL database.

This plugin based on ali-rds, if you want to know specific usage, you should refer to the document of ali-rds.

Configuration

Change ${app_root}/config/plugin.ts to enable MySQL plugin:

export default {
  mysql: {
    enable: true,
    package: 'egg-mysql',
  },
}

Configure database information in ${app_root}/config/config.default.ts:

Simple database instance

export default {
  mysql: {
    // database configuration
    client: {
      // host
      host: 'mysql.com',
      // port
      port: '3306',
      // username
      user: 'test_user',
      // password
      password: 'test_password',
      // database
      database: 'test',
    },
    // load into app, default is open
    app: true,
    // load into agent, default is close
    agent: false,
  },
}

Usage:

await app.mysql.query(sql, values); // you can access to simple database instance by using app.mysql.

Multiple database instance

export default {
  mysql: {
    clients: {
      // clientId, access the client instance by app.mysql.get('clientId')
      db1: {
        // host
        host: 'mysql.com',
        // port
        port: '3306',
        // username
        user: 'test_user',
        // password
        password: 'test_password',
        // database
        database: 'test',
      },
      // ...
    },
    // default configuration for all databases
    default: {

    },
    // load into app, default is open
    app: true,
    // load into agent, default is close
    agent: false,
  },
}

Usage:

const client1 = app.mysqls.get('db1');
await client1.query(sql, values);

const client2 = app.mysqls.get('db2');
await client2.query(sql, values);

CRUD user guide

Create

// insert
const result = await app.mysql.insert('posts', { title: 'Hello World' });
const insertSuccess = result.affectedRows === 1;

Read

// get
const post = await app.mysql.get('posts', { id: 12 });
// query
const results = await app.mysql.select('posts',{
  where: { status: 'draft' },
  orders: [['created_at','desc'], ['id','desc']],
  limit: 10,
  offset: 0
});

Update

// update by primary key ID, and refresh
const row = {
  id: 123,
  name: 'fengmk2',
  otherField: 'other field value',
  modifiedAt: app.mysql.literals.now, // `now()` on db server
};
const result = await app.mysql.update('posts', row);
const updateSuccess = result.affectedRows === 1;

Delete

const result = await app.mysql.delete('table-name', {
  name: 'fengmk2',
});

Transaction

Manual control

adventage: beginTransaction, commit or rollback can be completely under control by developer
disadventage: more handwritten code, Forgot catching error or cleanup will lead to serious bug.

const conn = await app.mysql.beginTransaction();

try {
  await conn.insert(table, row1);
  await conn.update(table, row2);
  await conn.commit();
} catch (err) {
  // error, rollback
  await conn.rollback(); // rollback call won't throw err
  throw err;
}

Automatic control: Transaction with scope

API：async beginTransactionScope(scope, ctx)
- scope: A generatorFunction which will execute all sqls of this transaction.
- ctx: The context object of current request, it will ensures that even in the case of a nested transaction, there is only one active transaction in a request at the same time.
adventage: easy to use, as if there is no transaction in your code.
disadvantage: all transation will be successful or failed, cannot control precisely

const result = await app.mysql.beginTransactionScope(async (conn) => {
  // don't commit or rollback by yourself
  await conn.insert(table, row1);
  await conn.update(table, row2);
  return { success: true };
}, ctx); // ctx is the context of current request, access by `this.ctx`.
// if error throw on scope, will auto rollback

Advance

Custom SQL splicing

const results = await app.mysql.query('update posts set hits = (hits + ?) where id = ?', [ 1, postId ]);

Literal

If you want to call literals or functions in mysql , you can use Literal.

Inner Literal

NOW(): The database system time, you can obtain by app.mysql.literals.now.

await app.mysql.insert(table, {
  create_time: app.mysql.literals.now,
});

// INSERT INTO `$table`(`create_time`) VALUES(NOW())

Custom literal

The following demo showed how to call CONCAT(s1, ...sn) funtion in mysql to do string splicing.

const Literal = app.mysql.literals.Literal;
const first = 'James';
const last = 'Bond';
await app.mysql.insert(table, {
  id: 123,
  fullname: new Literal(`CONCAT("${first}", "${last}"`),
});

// INSERT INTO `$table`(`id`, `fullname`) VALUES(123, CONCAT("James", "Bond"))