##mysql-dbhelper

A simple node-mysql utility to help you work with db operation easily.

###Install

npm install mysql-dbhelper

###Get Started

dbHelper = require("mysql-dbhelper")(options);
conn = dbHelper.createConnection();
sql = "SELECT name FROM users WHERE id=?";
userId = 1;
conn.$executeScalar sql, [userId], function(err, name){
    // work with name
};

###Options

defaultOptions = {
    dbConfig: {
        host: 'localhost',
        user: 'root',
        port: 3306,
        password: '',
        database: 'test'
    },
    onError: function(err){
        console.dir(err);
    },
    customError: null, // if specified , will hide original error, please catch real error by onError
    timeout: 30, // auto close connection after 30 seconds
    debug: false
}

###Note

1. All methods which start with a $ mean that the connection will auto close after execute.

For example:

conn.$executeFirstRow('SELECT * FROM users WHERE id = ?', [1], function(err, row){
    //The connection has been closed, you don't need to execute `conn.end()`
});

**2. Connection will auto close if db error occured:

sql = 'INSERT INTO users(email, password) VALUES (?, ?, ?)'; // This will cause a error
params = ['[email protected]', 'bar']
conn.insert(sql, params, function(err, success){
    if(err){
        console.dir(err);  // Don't need a `conn.end`
    }
    else{
        // Do other things and don't forget close the connection
        console.log('success');
        conn.end();
    }
});

This can be handy if you use CoffeeScript:

conn.insert sql, params, (err, success)->
    return cb(err) if err # Don't need close connection if error occured.

    #Do other things and don't forget close the connection
    console.log 'success'
    conn.end()

3. params can be omited in every api. If your sql don't need a param, just omit the second param.

For example:

conn.$execute('SELECT * FROM users', [], callback);

is equal to:

conn.$execute('SELECT * FROM users', callback);

##api

###conn.execute(sql, [params,] callback)

Execute a sql query:

conn.execute(sql, [params], function(err, res){
    console.log(result.length);
    console.log(result.insertId);
    console.log(result.affectedRows);
});

###conn.executeScalar(sql, [params,] callback)

Execute a sql and return first row and first column value, return null if don't have one.

conn.executeScalar(sql, [params], function(err, val){
    console.dir(err);
    console.log(val);
});

###conn.executeFirstRow(sql, [params,] callback)

Execute a sql and return first row, return null if don't have one.

conn.executeFirstRow(sql, [params], (err, firstRow){
    console.dir(err);
    console.dir(firstRow);
});

###conn.executeNonQuery(sql, [params,] callback)

Execute a sql and return affect rows count:

conn.executeNonQuery(sql, [params], function(err, affectRowsCount){
    console.dir(err);
    console.log(affectRowsCount);
});

###conn.update(sql, [params,] callback)

Execute a update query:

conn.update(sql, [params], function(err, success, affectedRows){
    console.dir(err);
    console.log(success);
    console.log(affectedRows); //Note: affectedRows is real affected count
});

###conn.insert(sql, [params,] callback)

Execute a insert query:

conn.insert(sql, [params], function(err, success, insertId){
    console.dir(err);
    console.log(success);
    console.log(insertId);
});

###conn.exist(sql, [params,] callback)

Execute a sql query, return true if has a query result

conn.insert(sql, [params], function(err, exist, result){
    console.dir(err);
    console.log(exist);
});