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.js to enable MySQL plugin:

exports.mysql = {
  enable: true,
  package: 'egg-mysql',
};

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

Simple database instance

exports.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:

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

Multiple database instance

exports.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.mysql.get('db1');
client1.query(sql, values);

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

CRUD user guide

Create

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

Read

// get
const post = yield app.mysql.get('posts', { id: 12 });
// query
const results = yield 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 = yield app.mysql.update('posts', row);
const updateSuccess = result.affectedRows === 1;

Delete

const result = yield 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 = yield app.mysql.beginTransaction();

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

Automatic control: Transaction with scope

• API：*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 = yield app.mysql.beginTransactionScope(function* (conn) {
  // don't commit or rollback by yourself
  yield conn.insert(table, row1);
  yield 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 = yield 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.

yield 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';
yield app.mysql.insert(table, {
  id: 123,
  fullname: new Literal(`CONCAT("${first}", "${last}"`),
});

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

Questions & Suggestions

Please open an issue here.

License

MIT