mysql-connector

NodeJs mysql helper. This library will help you to manage connection and operation with your MySQL server. Base on mysql module, this library add helpers to simply you interaction with the data layer of your application

Introduction

To install simply run the npm install command

npm i mysqlconnector

The library offer two main approach of a SQL operation: query and transaction
To connect to the database you have to use the MySqlConnection class

    const connection = new MySqlConnection('localhost', 'username', 'password');  
     
    connection.connectAsync().then(() => { 
        
        connection.queryAsync('SELECT * FROM users').then((results) => {
        
            results.forEach(user => { console.log(user); });
            
            connection.closeAsync().then(() => { console.log('connection closed'); })
          });
     });

The use of Promise simplify the use of the MySqlConnection object

    const connection = new MySqlConnection('localhost', 'username', 'password');
     
    connection.connectAsync()
        .then(() => { })
        .catch((exception) => {
            console.error('something bad happened', exception)
        });

The same goes for the use of a query

    const connection = new MySqlConnection('localhost', 'username', 'password');
     
     ...
     
    connection.queryAsync('SELECT * FROM user')
        .then((results) => {
            ...
         })
        .catch((exception) => {
            console.error('something bad happened',exception)
        });

Helpers

To simplify basic queries like create, drop, insert, select ... The library contains some query builder than can be use in a fluent way

Example of select

    const query = Select.Table("users");
    console.log(query.toString());
    // SELECT * FROM users
    
    const select = Select.Properties("username", "email").table("users").where("email = 'user@email.com'");
    console.log(select.toString());
    // SELECT username, email FROM users WHERE email = 'user@email.com'

Example of update

    
    let user = { username : 'user', email: 'user@email.com' };
    
    user.email = 'user1@email.com';
    
    const update = Update.Table("user").fromModel(user).where("email = 'user@email.com");
    console.log(update.toString());
    // UPDATE user SET username = 'user', email = 'user1@email.com' WHERE email = 'user@email.com'

Transaction

The library contains also a helper for transaction. The transaction will be automatically commit if no error occurred. If any thing goes wrong the rollback will be executed. Using TypeScript with async / await it allows you to have a nicer way to make sure all your operation happen in the same transaction

        const mySql = new MySqlConnection("localhost", "root", "root", "test");
        const dbContext = new DbContext(mySql);
        
        await dbContext.inTransactionAsync(async () => {
            
           await dbContext.executeAsync(Insert.InTo("user").fromModel({
                Email: "user1@email.com",
                FirstName: "toto",
                LastName: "toto",
                username: "toto",
            }).toString());
        });

The dbContext can be pass to other function and the inTransactionAsync function can be call again with impacting the first call, it still will be one transaction

        const mySql = new MySqlConnection("localhost", "root", "root", "test");
        const dbContext = new DbContext(mySql);
        
        
        function async addUserAsync(dbContext, user) {
            
            await dbContext.inTransactionAsync(async (dbContext) => {
                
               await dbContext.executeAsync(Insert.InTo("user").fromModel(user).toString());
               
               await this.addPasswordToUserAsync(dbContext)
            });
        }
        
        function async addPasswordToUserAsync(dbContext, user) {
            
            await dbContext.inTransactionAsync(async (dbContext) => {
            
                // Generation of complex password hash
               await dbContext.executeAsync(Insert.InTo("user").property('password', user.password).toString());
               
            });
        }